Comment by bluGill

> I've invested thousands of hours into building custom, multi-million-dollar machine tools at my day job

One key is find a hobby that is enough different from your day job you are not burned out of doing it. I can write code at home and sometimes I do - but most of the time I'm burned out after doing that for my day job. However I can still bend the sides of a ukulele, use CAD to design a new switch housing for some manual machine, practice trumpet, or other such tasks that are not related to my day job. I personally am not interested in editing a video (which takes a lot of time to do well) so you won't see me on youtube, that too is something I could do if I was interested in it.

Though with kids often all I have time for is cooking a meal before getting them to bed and then I'm off to bed myself. I wouldn't trade it for the world, but there is limited time and so there are a lot of things I want to do that I don't have time to do.