Hosting the Olympics is always an economic disaster. There is no reason not to use the venues long after. Why can’t the stadiums be used by professional sports or give them to the local high schools or colleges? Same with the swimming pools or turn them into city run public pools. Let a hotel chain buy out the dorms and charge extra to stay in the Gold Medal rooms. Huge parking lots should be a cinch to sale to developers since the land has already been leveled. Bottom line, it’s ridiculous not to continue to use them or set up permanent ones as you said. Ack, but then you’d have complaints about the home field advantage.
Big facilities have big maintenance and utility costs.
As you say, not all “gifts” are valuable.