BitWrangler wrote on Today, 13:30:

PS/2 machines were decommissioned from industry in truck loads, but were unpopular for personal use secondary market due to MCA and expense of upgrades. Thus they had a period of being dirt cheap and highly available. Which translated into being scrapped by the truckload also. Late 90s you could still hope to put a few hundred Mhz in the case of an old AT 386 or 486, not so much with a PS/2 box. So it was a total lost investment into obsolete stuff, whereas AT bits might be more adaptable and save you $50 or so on the next configuration. It is possible that AT machines are over represented now in the survivors. 92 or 93 it was probably biased in favor of proprietary form factors in the retail chain stores.

Seller has loads of PS/2 stuff.
So much so that he threw away cases that had bumps or needed repair, leaving boards behind.
Maybe I have to investigate further into his lair.

Is this gonna be a rabbit hole?

I'm a simple man. I see a Socket 370 board with Universal AGP, ISA slot and Cyrix/VIA CPU support, I buy it. (Seller's photo)