Those mercenary slaves were actually a big part of why the Ottomans did so well to start with. When they boys were taken they were given exams and the 10% that

Those mercenary slaves were actually a big part of why the Ottomans did so well to start with. When they boys were taken they were given exams and the 10% that did the best became bureaucrats in a sort of version of the Chinese system. Exam based bureaucracy is a Big Deal when you're competing with aristocracies. But eventually offices became hereditary and the normal sort of Chinese late dynastic rot set in.