What if the British Never Colonized Australia?

The first question is irrelevant.

The main thrust of your contribution is to insert a completely different scenario into this one, requiring a PoD back in the 16th century.
Further, given that the Dutch interest was ever in trade (and the lucrative spice trade to boot), one might suggest that the barren and spiceless Western Australian coast is a rather poor substitute. I might also observe that nations never really gave out consolation prizes; the past isn’t the same as the uncompetitive modern school playing field.

In any event, the OP is clearly talking about events that flow from the American Revolution as being the change here, or the PoD. My argument was and is that the roots of British interest in Australia stretch back further than this and aren’t tied directly to it as in the American-centric interpretation.

The reference to the 16th century is what would be needed to preempt the Dutch for the DEI.

Evoking the Anglo-Siamese War of 1687 as somehow ending English and then British interests in the area until after the end of the American Revolutionary War is a bit of a long bow to draw, but an entirely different topic. The rest of the first paragraph is simply what happened historically.

In the second, you go off into territory that doesn’t make sense and involves multiple points of departure:
PoD 1.) Britain, whose interests predate 1788, simply decides not to do anything about them
PoD 2.) The Batavian Republic, whilst a French client State prior to 1806 and a Napoleonic puppet kingdom thereafter, manages to send out a colonisation fleet or two through the British blockade, settle on a completely different side of Australia than they have ever shown any interest in.

The window isn’t 15-25 years, it is a whole lot narrower: 1788-1794. After that point, there is no opening for the Dutch to pony up and establish colonies anywhere.

On the third paragraph, the British didn’t hand out consolation prizes to the Dutch, but returned those possessions they did not see as vital to keep. Control of the Cape was a vital strategic asset, whilst removing others from India was simply par for the course. The other important part missing in your scenario is that the DEI were hugely, hugely more valuable than a few marginal Australian colonies that were not even fully self sufficient in food until 1804. Australia was no prize.

I would draw a distinction between the Cape Colony and Dutch possessions in the Far East, where there was much less of a European population at this time. Australia has no spices, nor cash crops and, until the discovery of gold, saw almost only agricultural based settlement.

Further to that, the Netherlands lacks the population base, military or economy to support settler colonisation. No matter how many increasingly convoluted hoops one jumps through in order to postulate a Dutch Australia - and these efforts, by nature of their multiple PoDs and extremely strained series of assumptions are particularly convoluted in the hoop department - that is an area which come up as a realist constraint.

As said before, Britain had real interests in the area that went beyond ‘a place to dump convicts’ and these would not simply evaporate in the very unlikely event that the Batavian Republic manages to put down a settlement at what was then the farthest side of the world.

See MAP.




Comparison India



Comparison North America



During the age of colonial imperialist aggressions, Britain, France, the Netherlands, Portugal and Spain used the semi-rigged and full rigged sailing ships to explore spice routes to eastern Asia. They fought and squabbled on the world ocean and exported their local societal troubles onto the rest of the planet. Depending on how shrewd the aggressors were and how resistant the local inhabitants were or became, the colonial imperialist aggressors imposed rule or settled into discovered new lands. They used navigatable rivers to make inward encroachments on the local human inhabitants. 

In the case of India, the land was pre-settled  and fractured into political subdivisions. It was possible for the British to nibble the region one piece at a time pitting one Indian state against another Indian state and thus establish an "empire" via technological superiority, political gamesmanship, and DUMB luck.  This was seen previously in history. It was how Rome established her empire in the Mediterranean basin. The method only works when another polity is weak and disorganized and the distances and resources and means expended are not cost prohibitive and the climate is "friendly" to trekking on foot or afloat on the rivers.

In the case of North America, the climate was friendly, the rivers plentiful, the local peoples were hunter gatherer proto-agriculture stage above the Rio Grande River and there were very few of the local inhabitants. YET the British stayed fairly close to the seacoasts in the east. It was left to Americans, after we threw the British out, to carry on the continental settlement across the midband latitudes. Gold in California and internal American politics shaped that drive. There was no British incentive and they did not endeavor. Notice that factor in how sparsely and unevenly and poorly Canada was settled, even though it remained a part of the "empire". Outside the Saint Lawrence River Valley, the internal communications  by river and trek was hindered by harsh climate. The coasts, reachable by ship were settled; but down to the present, the interior might as well be considered "underpopulated". As an aside, the United States exhibits the same coastal population concentrations and an underpopulated interior; but we still have dense populations in our great plains compared to Canada. Rivers and trek friendly terrain plus WEATHER accounts for that outcome.                     

Look at Australia. Climate indicates coastal settlements and the hunter gatherer stage local inhabitants indicates colonial settlement rather than imposed rule on a local polity by a foreign imperialist aggressor. 

The location of Australia that far south off the spice routes, its horrible interior climate, lack of easy rivers and gentle climate for trekking all combined to render it almost last by default for European aggressors to find and settle. The British took one look at it, at first, and decided it was a place "fit for convicts".   
 
The French actually looked at it and settled for strip mining New Caledonia instead. 

The "convicts" and later settlers built themselves a country anyway.  Their settlement pattern followed the geophysical access and climate realities, which as a sidebar is WHY the Allies *(ANZACs Americans) in WWII battered their way through New Guinea and moved through the Philippines rather from India and the Malayan straits, or through the eastern half of Dutch held Indonesia. By ship, by railroad logistics and supplied local industry and agriculture and by climate, eastern Australia was the only way to go.   

You do know that a south to north railroad and paved road to DARWIN from Alice Springs was a postwar endeavor? That is how tough the interior of Australia was and is to cross. Only necessity compels lazy humans to do "difficult" things like that. 


 

Do I know that the Alice Springs to Darwin railway was completed in 2004? Yes, I certainly do and remember it well; I used to drink with a few blokes who worked on it.

Do I know how tough the outback is to drive across? Well, I did it for 15 years.

Australia isn’t a foreign topic for me.

So if British Empire focus on there American Colonies instead Australia

Who will take it ?
the Dutch ? nope their interested in trade Post and they got Indonesia, why to bother with that Australia ?
France were interested in Colonise Australia but French Kingdom was edge of bankruptcy,
The French Empire under Napoleon had similar plans but had issue with British Empire.

So left the British who need resupply harbour in that part of World, Sydney bay would perfect.
But that is all, a harbour with docks and small settlement.

Although this here would be nightmare scenario: in 1830s Leopold I claim Australia as Belgium Colony...

That was just after the China investments and the great northern mineral deposits were developed? 

I neglected one factor for Australia.




The whaling zones were small, but between 1820-1880 they were there.  Of more importance (Falklands and St Georges for example. M.), to the British were the Atlantic zones, but Australia was close to those Indian Ocean zones.