Zeroing in on an earlier comment upthread:
"but what do I really want to add to the world and do with my remaining years."

I've recently had to remind myself of stuff I subscribe to.

1, there are a few geniuses who are changing the world. I am not one of them.
2, I could sacrifice a great amount and go work for those geniuses. (E.g., quit my job, possibly have to divorce Alyse, and try to go get a job at SpaceX.)
3, from EMS, I learned: everyone's number comes up at some point. Mine might come up later today.
4, "a butterfly in South America flaps its wing and causes a hurricane in North America" is, I believe, not an accurate description of fractals and ripple effects, but by the same token, I believe it is accurate that there's some truth to it.

So I follow "think globally, act locally", writ large. I cannot make the world a better place, but I can make/inspire/lead the people around me to be a bit better, and that's useful.

The particulars, then, are just the medium, but the medium itself isn't the relevant part to my answer.