I repeat it anyway.

Those that treat their core territory in a rational manner — forfeiting it in accordance with strategic imperatives, as, for example, several Germanic tribes did repeatedly during the Migration Period — get wiped out.

Getting wiped out isn’t rational. Most likely they overlooked the fact you need a place to live. Or, they would have been wiped out anyway, because they couldn’t defend their core territory.

Needing to see your territory as sacred to be able to take the bourgeois/kingbird/rooster strategy is irrational. Its main flaw is inflexibility. Having devoted a couple generations to sacralizing, then if I need to move I can’t reasonably do so. It’s a much better idea to sacralizing something that’s actually sacred, like family or community. Defend the land not because it’s sacred per se, but because the people living there are.