Tribal management often involves power struggles. One thing that's been shown again and again–subjugating another tribe, taking it over–it almost never works. It can take hundreds of years before the two tribes get into sync, if ever.
On the other hand, granting independence to a rising tribe, letting them go–this is harder to swallow but it generally leads to a quick and beneficial relationship between the two new groups.
When Atari was struggling after it was acquired by Warner, many top programmers left, some to start companies like Activision. Activision, ironically, was one of the bright spots for Atari after that. The passion and creativity of the nascent group was exactly what the original group needed.
Or consider the excellent relationship that the UK has with both the United States and India. In both cases, the wars of independence weren't as nearly brutal or as drawn out as they could have been.
While conventional views of power and authority seem to indicate that you should co-opt and capture other tribes, you can often achieve more by freeing your own people to maximize their vision alongside yours.