I'm unclear why there seemed to be so much focus on a bridge/tunnel hybrid? It seems far more complex and expensive than a straight-forward bridge, albeit that the latter would be a huge project in itself. constructing the two artificial islands on their own would look to be a massive programme. True you might need something similar for a bridge to handle the assorted 'legs' across the channel but they wouldn't need to be that complex and then link into an underwater section.
A bridge route would have some advantages over a tunnel, such as being able to use road as well as rail links and also if problems occur it might be easier for emergency aid to people trapped by any problems. On the other hand, while a total failure of the tunnel, with it being flooded is far more destructive than say a link of the bridge going down its probably markedly less likely. Although if one span went down on a bridge would the resultant forces at work cause damage or even disruption to the others? Not sure on that.
Possibly one key advantage a tunnel has which wasn't mentioned on that link is that it doesn't interfere with sea traffic. The Channel may no longer be the most congested stretch of water in the world but its still very busy and seeing to construct a massive bridge above it is going to cause a fair amount of disruption, let lone the problems of some sort of collision between shipping through the channel and ships being used in building the bridge. Plus with the larger sizes of ships its even possible that one of the huge transporters on the sea nowadays might end up too high for a bridge designed and constructed in the 60's say.
Taller new ships would adopt folding masts to avoid hitting the Channel Bridge at high tide and light loads. Shipyards could brag that their ships met the latest "Channel Bridge" standards similar to the way that shipyards currently brag about "Panamax" certification.