New weapons in common quality usually popped for everyone very quickly. And were you really unlucky it's was a matter of seconds to find a trade by crafting some metal out of unwanted items.

Was kind of a meta-game, but yes definitively paved the way for virtual goods stock market. Some social science researcher should totally investigate that (if not already done).

Example of an exchange: https://backpack.tf/

Edit: Lot apparently they also suffer from economic crash sometimes like with bitcoin https://www.eurogamer.net/articles/2019-07-26-team-fortress-...