Sometimes you want an old school rig to run old school games as they don't always run the same or at all in emulators (and may not want the experience of having to run the emulator to play the game).
But agreed, "I", a manic old school console player who runs old game consoles using original cartridges/discs as well as running them on pc emu's (as well as old pc games like Mean 18 (golf), ...) wouldn't spend a lot on legacy upgrading for a generic old school pc. I find old parts or whole pcs in Salvation Army stores, at Flea markets or on eBay on the cheap, might take a little longer but makes it fun too (like a scavenger hunt ;+)
Manic49er