Escape hatches can work. I took a bet on Mapzen a few years ago - when they shut down my employer had features that depended on their WhosOnFirst API. Because the data behind that was openly licensed we managed to migrate off it to our own (MySQL spatial table-based) solution before the shutdown.
It was still a big pain, but it would have been a whole lot worse without that escape hatch.
Of course, the benefits of taking on this risk may often be worth it. Smart bets don't always pay out.