At least this one is not acting cowardly by running away with all the money. However, it's true though that at the end of the year there are usually so many things that happened to the whole bitcoin community even the biggest dump back then happen December-January 2018 if I'm not mistaken and that's such a scary thing to happen.
But the fact is that the state of the bitcoin community is not determined by month, this is just a coincidence. And for those exchanges that are closed, they are actually losing competitiveness and the current state of the market community is not good, so most companies will close in the 4th quarter of every year.