Not always, in the past you'd get a top tier graphics card for 350 Euro, now that same level card is 2000 Euro, that, for example, has gone up through the years, it's not that straightforward.
Normal people might keep machines longer, corporations do not and price is irrelevant to them, they change machines after X amount of years and that's that.
R&D won't slow down, you can't afford to do that, the actual release of products, yes, that can be postponed, R&D never, stagnation means getting overtaken and again, normal people and gamers are irrelevant, that's peanuts compared to corporate buyers, why do you think that the CCD's AMD produces are the same all the way through the range? They can sell the same CCD for 10 - 20 times the price if it sits inside a server chip.