Seems to me that retro builders if they were purists would have two systems, a lowly 386 (the Beater Daily Driver) and then a modded Pentium (the weekend joy ride) and just completely skip over the 486 days.
That's reasonable, and I'm taking a similar sort of approach myself, although not with just two systems. For most games from, say, the 1992-1998 range, give or take, I'm assembling a nice 430HX Socket 7 system. (I had a P133, but it died, so I'm building a new and better P1.)
For earlier games, I may eventually put together a 386 or high-spec 286, but for now, my Amiga covers that era to a reasonable degree. It's not quite the same as a PC, but I'm happy enough with it... like anything else it has its own strong and weak points.
I also have an 8086 machine for really old software, and 2000-up titles are covered by my main machine, or one of my PIIIs, or whatever is handiest.
On the other hand, I still kinda want a 486 anyway, just to screw around with. I guess it's partially nostalgia-- that's what I had when I first really started getting into computers. It was the first time I assembled a machine from parts, and I played Doom and Raptor and some of those other 'classic' titles on a 486, I first got onto the internet with a 486, first experience with Windows 95, all sorts of stuff like that. Plus, for some reason I just find it interesting to play with orphaned technologies like VLB and EISA.