The problem is explained at the end though. They were made to be collected. Mass produced collectable rarely really explode in value because they are kept preciously by their owner. If there was 10K "rare" beanie, chances are there are still the same 10K available. The buyer market however is much smaller.

That happens with plenty of stuff even in the antique range. Japanese, Chinese export silverware/tableware from beginning of the last century trade for poundland level pricing. Dragon-ware or similar stuff brought back by US soldier looks fancy and is similarly worth hardly anything. Even the rarest, best quality lithophane are very reasonable in price i.e. in the tens of dollar range. A good, purchased to be used, brand of tableware from similar period can cost 10 times more, rarest pieces going for hundreds.

I think it'll take a lot longer than that, it'll take years for a majority of them to be thrown away before they're rare enough to be worth anything.

Literally every family I know had an enormous collection of them. That fad was huge.