The PC (or the Mac) is, of course, a long way from perfect, but you can count me as another data point for the theory that hardware pretty much reached "good enough for just about anything" a few years back, and I'm saying that as someone who is a programmer and a gamer, so for Joe Q. Public running Office and Chrome this point was reached even sooner.
Core 2 Duo w/ 4 gigs of RAM was, I'd guess, basically the tipping point for normal users, Nehalem w/ 8 gigs of RAM, GeForce 4xx and an SSD for the system disk was the tipping point for people like me.
I used to upgrade my system yearly (buying parts off Newegg, reusing existing bits where they made sense to do so) but now it is more like every three years and growing each time.
There are, of course, lots of ways PC manufacturers can turn this around with increased novel input methods, more hybrid devices and especially an increased focus on higher resolution screens (which has a multiplier effect because if you truly boost your on-screen resolution, you'll soon start feeling cramped by your CPU, GPU and memory again), but the days of tossing out more powerful CPUs, GPUs and a bit more RAM (and then calling it a day as far as new features are concerned) are over.
When I upgraded from my C2D to a first gen i7 was the first time I didn't feel pain and the need to upgrade... I did go with an SSD at that time, and spent about $1500 on that desktop iirc (main case, not monitors, keyboard etc)... I recently replaced it with AMD's top 8-core option, which works better for me than an i3/i5 at that price.
I only upgraded because my system was unstable, and it was likely the motherboard (which I would have to replace the mb+cpu) or the power supply, either way pretty much the same effort/cost as upgrading both. New system runs great.. the irony is most of my non-work stuff gets done on my htpc in the living room, or my nexus tablet. My c2d macbook pro, and my desktop aren't used that much.
Core 2 Duo w/ 4 gigs of RAM was, I'd guess, basically the tipping point for normal users, Nehalem w/ 8 gigs of RAM, GeForce 4xx and an SSD for the system disk was the tipping point for people like me.
I used to upgrade my system yearly (buying parts off Newegg, reusing existing bits where they made sense to do so) but now it is more like every three years and growing each time.
There are, of course, lots of ways PC manufacturers can turn this around with increased novel input methods, more hybrid devices and especially an increased focus on higher resolution screens (which has a multiplier effect because if you truly boost your on-screen resolution, you'll soon start feeling cramped by your CPU, GPU and memory again), but the days of tossing out more powerful CPUs, GPUs and a bit more RAM (and then calling it a day as far as new features are concerned) are over.