There could be good or bad development teams from any country. Being Turkish may have something to do with their poor performance if, for example, there are some sort of government restrictions that are creating difficulties for them. Or, perhaps it is very difficult to find Turkish devs. Or, maybe there is some cultural machismo that prevents a poor leader from recognizing that he needs help.
However, any of these could happen in any country and I don't think it is fair to make a broad statement about a whole country. After all, it was a Turkish company that created what is probably my favorite game of all time, the OG Warband. And, if you are here *****ing, it is probably because it was yours too.