I think, only in rare circumstances, like rates being unusually high, such that they will almost certainly go down.

Locking in rates costs money. Nobody will give you a reduction in risk for nothing. Often they are a bad gamble, because if you're in a long term loan, even if the rate is variable, the length of the loan itself provides the averaging to de-risk that.

Most people work with spot rates for all sorts of stuff they consume. You don't get to negotiate a 30 year rate on steaks, milk or gasoline. You can still buy those things when prices are low and average things.