Agree, just look at DayZ. Players stuck with that through extreme buggyness. Sure it might not have the same number of players as it once did but there were periods during which players were putting up with a lot of bugs.
I don't really 'get' DayZ, but I also know that it was a pay-once game, not free to play. Once you've paid the money you might as well get your fun out of it. But if you're constantly losing items and getting frustrated by bugs what's the incentive to keep playing and possibly giving Niantic money?
Because we're believers! And there's no subscription cost and we've already paid, and all our friends play it too, I guess...