It worries me that the flight to tablets and other not-PCs will cause a return to the $4000 PCs of the 90s (at least, I can remember my father paying about that for a 486DX)
I wouldn't worry too much about this. Shrinking markets usually mean price wars. As PC growth stalls, today's equivalent of your father's $4000 PC now sells for under $400.
Really? Wouldn't less players mean each individually has more influence on the market, therefore price hikes?
Things seem to get more expensive in shrinking markets (magazines, for example)