In fact the gay uncle is behaviorally driven to do things that are evolutionarily detrimental. Like spending time mating, flirting and being with other gay men. I don't really see gay men abandoning all of that to care for a nephew or something like that.
Take Sam Altman for example. He's not spending time caring for other kids in his immediately family. He's sinking time into getting rich from openAI and snogging his current partner.
The gay uncle gives about as much of a shit about nephews in the family as the straight uncle which is virtually for all intents and purposes: zilch.
I'm saying capitalism forces our hand to the maximum extent such that it eats away all time involving free favors to other people. The ladder is unlimited in height.
So if I have 8 hours or 16 hours available for productive work it doesn't matter, I'm going to allocate all of it to capitalism because that's a never ending hole.