First, historicaly (and emotionaly on my part) I have a hard time taking the premise that the status quo will stay the status quo. I have this belief that some bright person is going to come along and blow all our pipe dreams away.
When quark theory was invented, it didn't change the conservation of mass-energy. When quantum computers are invented, it won't change the fact that they're still Turing machines. If it does, that's a revolution; I'm not waiting. A single tape Turing machine has the same computational ability--though not the speed--of a multitape Turing machine, of a multihead Turing machine, of a multihead multitape Turing machine, of a register machine, of single/multiple instruction single/multiple data multiple register machine, of the lambda calculus, of recursive function theory, and of pretty much every other rich computational system every invented. If you still don't agree, I can only steer you to pretty much any first year formal logic textbook. Eric