If it was easy enough to rent my desktop while I'm not using it (such that I can get it back whenever I need it myself, within a few minutes at most), I would happily do it.
Do you mean when the computer is not in use or “unused” in the sense that even when gaming it is just being used for gaming and not something “productive”.
2 very different arguments and not fully clear which you are trying to make.
This. No judgement on any particular use. Just worth a reminder that the most advanced machines every produced make this magic rocks that sit there idle most of the time.
You could say that about litterally anything. Food, housing, fuel, heat, water. There are always solutions for better optimizing global resource allocation - especially if you're willing to ignore the wants and rights of the people.