I don't think this Doomsday Scenario will be the case. As Steve Jobs once said, we will always need trucks. While most people can do their daily driving in (relatively) easy to use cars or even commute by mass transit, we still need trucks to move around the big items. Music and video production, intense graphics, animation, etc. will still require more powerful (and probably different interfaced) hardware.
Which is why I said "But I think it's a possibility that the golden age of pro audio riding on the coattails of consumer-oriented computers may be in its twilight years." Sure, maybe some people can spend $10K-$30K on a tricked-out Mac Pro, and for sure, Pixar can. But I can't, and probably most people with home studios can't, either.