I'm not so sure it's "wealthy liberal jerks" who are destroying the thrift shop market. It's the eBay resellers, who are then selling to the "wealthy liberal elites" on the auction platforms (which don't auction anymore). When people are able to comb through thrift shops and buy a sweater for $3 and then turn around and sell it for $30 on eBay (while recording it onto YouTube for all to see), then places like Goodwill soon catch on.
I've been a thrift shopper since high school — my uncle, who was a "junker" taught what to look for and how to price it — but we were looking for legitimate antiques. Over the past 10 years, it has become more and more difficult to find good deals on anything. But now it has moved into clothing that is still functional and that used to be what poorer people would buy. Then I see YT videos of "resellers" who get into fights in the thrift shops, who swarm the Goodwill carts when they bring them out and make things really difficult for the employees. Goodwill (and other shops such as Savers) have created their own online platforms and anything donated to them is curated before it ever gets to the thrift shop floor. I have seen items on the floor that still have the old price tag on them, and then the Goodwill tag is marked up $2-3 more. It's gotten really ridiculous. But just go to a Goodwill shop and witness the insanity. The Millennial resellers are cut-throat about this stuff, because it's getting more and more difficult to find things they can resell.
Correction, I meant to say “wealthy liberal jerks” rather than elites... I’m pretty certain wealthy liberal elites aren’t shopping at Goodwill, but their kids probably are.