When the market turns around (and every time in the past it was "only going up" it eventually ended) then suddenly you have apartment complexes turning into condos to sell off capital and stop the bleeding.

The problem for people "on the ground/in the rentals" is that can force you to act when you're not financially prepared to - it's easy to find situations where someone can afford the rent; even afford the mortgage to BUY the apartment as a condo; but cannot afford the downpayment (or otherwise qualify for the loan).