I agree that the idea of crisscrossing the world to take every possible scenic selfie seems empty. For some people, it won't though. There's also so much more available to us than just this sort of consumption.
Personally, I've always had the itch to recreate as much of the computing stack I rely on as possible. I love the idea of running my own text editor in my own shell, written in my own programming language, compiled with my own compiler, running on my own operating system. Not because I think I would be pushing the state of the art forward or that it would be commercially viable, but just for kicks. The joy of truly understanding.
I think this is not a completely uncommon feeling, which is why a lot of programmers could look at Terry Davis and say "okay, aside from the obvious mental illness, the racism and the antisemitism, there is something there." He spent years building something with little value to anybody beyond himself. Zach and Tarn Adams spending twenty years on Dwarf Fortress also comes to mind, to the extent they are doing it for themselves. These projects require huge sacrifices on the part of their creators. The opportunity costs incurred shape their lives (e.g. the Dwarf Fortress decisions currently being made based on health insurance coverage). I can't imagine inflicting the programmer monk lifestyle that would come along with such long term non-commercial work on my young kids when the end state is just "Yeah, it's useless but I got a kick out of doing it."
Being honest, it's also hard to imagine that once my kids move out and I can pick a more austere lifestyle just for myself, I'll look at the remaining ~20 years of my life and say, "I think I will devote the rest of my life to this one single 'that would be kinda neat' drive."
If I had, say, 100, 200, 500 more good years where I could just subsist and pursue passion projects? I'd love to spend 10-20 years going down the "recreate all your software from scratch" rabbit hole.
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A thought on the "society needs death" idea: if my continued existence pursuing obscure hobbies without economic value is a drain on society, maybe the fix isn't that I must die at some arbitrary age fixed by evolution, maybe the fix is just a better way to account for the costs and benefits of our actions. Don't say nobody can spend 10,000 years jetsetting from tourist spot to tourist spot, just require them to offset it through their other actions so that on balance they've made a positive contribution.
