Around 2000 I remember building myself new PCs every time someone wanted a gaming PC; I'd sell them my existing system and build myself the new hotness. I'd always buy just where the price/performance curve was starting to go vertical, so the 2-3 month old machine was still quite a good "deal".
That stopped being effective sometime before 2010. Instead I'd recommend buying a decent enough machine and sticking a graphics card in it.
Yeah.. late 90's to early 00's was pretty peak builder era. I learned through a relative fluke how much going a bit over the top on memory and faster drives really helped over even a faster CPU/GPU a lot of the time for general use. My current computer is literally the first I've built in decades that I didn't max out the RAM... I mean, I kind of did as 2x48gb was the most I could get in DDR5@6000 and only use 2 slots (or it would run much slower).
4th gen Core series was the longest I'd held onto a single PC (close to 5 years total for a 4790K). I did a mid-cycle gpu and nvme upgrade and that was it. I bumped to a 3950X/5950X and now 9950X since... AM3 is really the first socket in a long time I'd done an in-place upgrade for any CPU. My daughter's Ryzen 2400 to a 5000 series, and my own build from a 3600 -> 3950X -> 5950X... the 3600 was a placeholder as I couldn't get a 3950X for a few months.
I couldn't even name half the CPUs I ran from 1998 to 2005 or so... it was such a blur of upgrades every 6-12 months... I'd upgrade my computer, my wife's, my son's... etc. Then, things just completely stagnated... I mean there's been progress, but it's over the course of years, not seeing 2-3x in under a year.