It used to be that you could assume that you would need a PC of some kind, for work/email/homework whatever, so upgrading the pc so it could do games made sense.
Roughly the same time as the 360 era I built a PC for uni, and the extra cost to get console-beating parts (and adding in that PC games were cheaper or pirated) was way better value.
Now Im not sure what I would do in the same position, a laptop and console costs significantly less than a PC that even matches it, and unis mostly stopped having any focus on CAD
PC is really the only place where you get super high end framerates+resolution+graphics-fidelity combinations. It's only really cost effective if you upgrade slowly—a new cpu here, a new GPU there, amortizing the costs over the years. And the nvidia xx80/xx90 models are never the ones you'd buy if you are trying to be cost-effective. They are high end damn-the-money-just-give-me-all-the-graphics cards.
[1] maybe back in the era where the PS3 was $600, but even then a xbox 360 was cheaper and mostly just as good fidelity-wise.