I think we can see that an exchange facing numerous problems may not be able to solve them, leading to its downfall. First is technology; I believe hacking is always easier than building. It takes a lot of work and effort to construct something, like building a house, but it only takes a hammer to break a hole in it and steal all your assets. Second is money; fewer people can resist the temptation of money. Yes, there's a lot of money involved. Why not take 10% from laundering black money rather than 1-2% from normal people? I believe people can see many problems, but I've just pointed out the two main ones.