HWD,
The future EU system you describe will be no better than the US one, and who do you think invented WAAS? You can already fly your magical GPS flight in the States.
The US system is backed by the US government, it's hard to think an operation run by private companies could be more solid than that. The US understand certification requirements, they probably wrote the book on aviation certification, and GPS is certified as safe over there. I can see why the EU might want their own system for political reasons, but I simply don't accept it will be better than the US one technically or operationally.
It's all down to money, IMO. Another example of rip off Britain???