I think that it's safe to say that hacking no longer is the main point to worry about. I personally consider insider theft to be a much bigger problem than hacking will ever be. Don't forget that most of the exchanges nowadays aren't used to operate a multi million dollar business, and especially so with the fact that they nowadays have direct control over potentially billions in digital asset value. It's far too easy to pretend that an exchange platform has been hacked, while in reality it's the operator himself that's behind the theft. After that they just release debt tokens that the exchange will later buy back to settle its debt, and people are more or less happy and move on like nothing has happened -- that's the trend in the last years.