Strange thing here is that stevec seems to be the only person with such problems. They have has several markets and if you take a closer look you'll see there appear to be several mm's, operating on the exchange. And no other claim. Why? If, as you say, they are about to shut down, there should be at least >1 complain of not paying out. Seems like this story might be a little bit more complicated.
it is indeed strange, that you hear so little from other users. NOt even anyone coming forward to say that for him everything works fine.
I believe that a great part of the market making happens very close to the servers. when they started out they had a super constant trading volume which was not the least impressed by volatility. This changed from one moment to the next when someone pointed it out on reddit and accused them of orderbook manipulation. Check the meanwhile closed official hitbtc thread here on bt and the historical data from bitcoincharts. It seems indeed, that most of the trading on hitbtc is not made by people who read (let alone write) anything here.
It is most likely that they have run into problems with their bank and that their account has been frozen or closed (happened to many others before - bitstamp, which changed from unicredit to raiffeisen and and others had the same problems - including myself).
In the end it doesn´t really matter why they are not able to pay people their fiat balances.