I haven't done long division in decades, am probably unable to do it anymore, and yet it has never held me back in any tangible fashion (and won't unless computers and calculators stop existing)

That makes sense. Some skills just have more utility than others. There are skills that are universally relevant (e.g. general problem solving), and then there are skills that are only relevant in a specific time period or a specific context.

With how rapidly the world has been changing lately, it has become difficult to estimate which of those more specific skills will remain relevant for how long.

I am rather positive that if you were sat down in a room and couldn't leave unless you did some mildly complicated long division, you would succeed. Just because it isn't a natural thing anymore and you have not done the drills in decades doesn't mean the knowledge is completely lost.