On the one hand, this doesn't surprise me, as many of us dream of creating something that will provide them with passive income and at least some relief from the household budget. On the other hand, it's as you say – we're usually talking about low- to moderately popular games, which in the overwhelming majority of cases won't generate a profit.

I don't have practical experience, so I can't comment on large companies and asking them to share code, etc., but I've heard from CDPRed and Polish game developers that large companies generally don't give a damn about old games. In fact, sometimes they even deliberately sell them for pennies to test the waters to see if it's worth investing in. Regarding paragraph 3, I also read this on the GOG forum. Many games can't be ported to new hardware, or it's very difficult to port due to various archaic features. Or "workarounds to code limitations" that no one but a single old developer knows how to solve.