Until there is some kind of law in place that makes companies financially responsible for this kind of blunder, it will proliferate. In the current state of affairs it's simply not economically justified to implement proper security.
It's not a stretch that there should be laws that affect all companies that collect data on their users. I hope it happens soon! These companies should be paying quite a bit in fines for these mistakes, not just a few thousand for a bug bounty. Otherwise our personal information will most likely leak and be all over the web.