About 17 years ago, I taught myself how to make mods/map edits for Halo CE on my family's Mac. On regular Windows, the tools are more straightforward; on Mac, they were less intuitive, had much less documentation due to fewer people working on it, and were generally pretty eh; this was all also pre Youtube, or right at it's start, so...no helpful video guide. You had to use an archive invalidator to flag any map you wanted to edit as a 'demo' map before you could edit anything to fool some registry value into permitting the edits, and then had to remember to flip it back again once you were done with editing (it could also break sometimes for no apparent reason).

But I (and many other people) used it all anyway to make all manner of oddball things for the amusement of ourselves and others

Hell, the Marathon games before that came in the mid 90's with their own editing software (more accurately, Marathon Infinity did), and it was insanely complex. Shit was basically a bunch of numbers in a database that you could play around with to affect items (og Forge was the map editor and Anvil the scenario)

And that's just a very niche segment of gaming, there are so many broader examples all around us of people doing things, not out of want for profit, but for desire to improve the world, for their own pleasure or entertainment, etc.

Bottom line, if you earnestly believe that...I almost pity you (almost). Unable to think in things outside of terms such as money