> Truth is, once youth passes, over time people become increasingly disinterested in others.

I find almost exactly the opposite is true. As you age your perceived value lessens, while you find the nuances of human behaviour ever more fascinating. Meanwhile many of the current cohort of twenty somethings seem disinterested in everything, including one another.

I would extend that to thirty somethings, so my generation as well.

Over time most of the people this age in my extended social circle kind of... faded. I don't know what caused this but I find myself increasingly socialising with younger people because they still haven't retreated to the comfort of their "me time" activities.