I suspect that thet haven’t gotten any less tolerant, just what people are willing to buy from them at a cost that covers justifies the inventory space given competition for the space has changed.
I also noticed a transition towards boutique style stores around that time. While the older stores may sell a box of books or bag of clothes for a few dollars, the newer stores would only sell items at their sticker price (or with a fixed discount during sales). Less product moved since people would only buy something when they felt it was worth the sticker price, rather than paying what they felt something was worth. The transition made space/economics more of a factor than it used to be.
Some of the old style stores still exist, but they are increasingly difficult to find.
Thrift stores were also a lot more tolerant of junk back then. If they could sell something, it didn't much matter if it was broken as long as the customer knew it was broken. They knew a lot of people were looking for cheap stuff they could fix, either for personal pleasure or to make a few dollars.