Not all of them are going bankrupt, some of them are just exit scam. They come in and pretend to be legit and try to get a lot of investors on their side and once they have made enough money they will quickly exit the market, taking investors money with them. Some of them are due to lack of funds though, but I think any exchange that can keep up should be blamed for it. Before you startup things like you should have it planned for a while.