Serious question, are PCs a growing market because "people are getting past" the obstacles or because this console generation has been around so long that each new game is only able to wring diminishing returns from the hardware and people are looking for a bigger jump in performance? Surely people will continue to buy PCs, but will the recent increase largely drop away in favor of new consoles once they arrive? (Eventually picking back up of course as the years age these consoles)
I'm one of those people who would rather buy a console despite the understanding that they will be outstripped in power in short order because I know it will be cheaper (the PC that PC gamers would actually want to play on certainly is more expensive than whatever the PS4 will be), simpler, and barring hardware failure will last me a long while. Sure the returns on subsequent games through the lifespan will be overcome by what's on a pc, but I won't have to worry about updating my rig to match those gains either. That's a fight I've no interest in fighting every year or every few years. Pair that with the exclusives the OP suggests Sony should give up, and consoles easily come out as the easiest and most cost effective way for me to game (Personal lifestyle choice).
I don't see this ebb and flow changing unless PC gaming becomes even cheaper and even more stream lined (Consider construction, compatibility, and performance. Maybe potentially something an actual full-on valve-made steam box could fix). As long as first party exclusives exist and consoles remain the easiest to use box, shouldn't this always be the way?