Mike asked; "I'm hoping to learn at least 1 thing...how (why?) is it possible to obtain practically uncirculated chips from small casinos that went out of business 20 to 30 years ago? Am I missing something?
I really want to trust the vendors."

Mike; Your question is a good one ... and perhaps my reponse can be added to Will's excellent reference website.

Other than the occassional "find" of a fogotten hoard of obsolete chips from a former casino owner ... or from a relative or partner of a living or deceased casino owner ... the obvious reason (to me) is that there are those so-called "greedy" dealers (and old-time collectors) who put aside chips as they are issued in their inventory and stock books (sometimes for decades) so that new chippers (like yourself) and experienced chippers (who are working their way back to the earlier issues) are able to obtain nice, new condition older chips.

The same principle applies to early roulette chips ... that some people decry the harvesting practice ... but are thrilled to add these gems to their personal collections. 20 years from now, someone else will be posing the same question you have asked today.

Like it or not; it's called ... "preserving casino history"