All electronics are getting harder to find with age, they are all being recycled like crazy. To be honest I am happy there is still a decent supply of the retro stuff around, some of the newer stuff is going from direct use to recycling way before it gets popular to collect ( a lost generation).
Sure reselling or giving the stuff away is better then recycling if there is demand in your area, but few people want to go through the effort of testing a board to maybe get $10 on ebay (before fees) and having to ship something (people are lazy).
The Pentium machines I try to save are the old servers/workstations with custom boards, EISA + PCI slots or MCA, and early chips (P60/66 then the later 90 and 133's). I also keep a few SS7 boards for last generation Cyrix, IDT, VIA, and AMD chips (before the other companies went bust) and some decent server boards (HX chipset). There are a lot of garbage chipsets out there I don't bother with, and I am not too crazy about Intel VX/TX chipsets either. Oh yea, I also have a working dual P200MMX board I need to install something oddball (real unix maybe) onto.
If you just want a Pentium for early games then 64MB of RAM and any chipset will probably work for you.
Collector of old computers, hardware, and software