Since 2012 it has been my opinion that only wildly impetuous people set up bitcoin exchanges.
It was highly amusing to read about for years, I lost interest a while back.
I recall Amir using his personal bank account to operate Britcoin. The days when mtgox frequently fell over quite often, if Karpeles was asleep people on the bitcoin IRC channel would call his mobile phone until he woke up. He appeared to do no testing of changes to his software before making it live.
I recall the Polish exchange that disappeared one day, the young men running it tried to increase the RAM on the single virtual server it ran on and accidentally reinstalled it. They had no backup and the private keys for about a hundred thousand BTC were lost. They went silent for a couple of weeks, when they reappeared they claimed they had got drunk for a few days when they lost hope of recovering the bitcoin.
Several hacks of bitcoinica, culminating in the time the source code was deliberately released but contained an important password which was rapidly used to steal the bitcoin.
Nefario setting up his own stock market and being genuinely surprised when he got some legal advice and was told that there are lots of regulations that he should have been following.
There was the exchange that thought they were super secure because only a few laptops could access the servers. The laptops had windows, microsoft office and skype installed. A staff member accepted a document from a phisher on skype and ran it with macros enabled, bye bye bitcoin.
The risks, difficulties and regulatory uncertainty mean that only wildly impetuous people set up bitcoin exchanges resulting in bitcoin exchanges being run by impetuous people who commit terrible blunders and try to keep going.
If you want to store some bitcoin and conclude that keeping it in an exchange account or wallet run by someone else is a terrible idea then running bitcoin software yourself seems like quite a hassle. You need to figure out which version of the software to use if there is currently a battle between different factions over block size or something then download, verify (days of 100% cpu) and store 200GB of blockchain. If you want to receive some BTC and you have not run your software for a while then you may have to wait hours for it to get recent blocks.