Safety in numbers.
Though I remember a certain family in World 11 of ~8/9 tribes which crumbled when we took down one of the tribes. Kind of says it all, they're just there to try and prolong themselves, not playing for the tribe.
I like them though. It shows me who's going to be easy pickings around my villa >
APOC W58 (I believe it was? not certain) was a funny family to watch, had maybe 600 players in it total? Including about 50 experienced good players hahaha