I think there are different hierarchies to climb in different ways, and hirarchies seem to be distributed in such a way that ass-kissing climbup one makes the majority of the total, still isnt the only one tho, or way.

Wanna hear something funny? I saw a youtube/national geo. Video about chimps, actually about the ass-kissing hiera.

There was a young imp who was helping the aging alpha, he wasnt the strongest, but he was still made alpha by the old alpha, and the grooming kept happening after said appointmment. Funny thin is, the strongest chimp wasnt chosen, and was second in command! He could beat both in single combat, but not while both teamed up.

So i guess the ass kissing stuff has a role, i guess it selects for team players ... but damn man fo they Get toxic and abusive. It sorts of gives the impression that were not worth keeping around ... but then i see someone save a dog and my heart melts for our species.