ebay, etsy, and people attempting to 'blow the scene open'.
That is the thing that is annoying. On the one hand you have super inflated prices for official games, which I think reproductions to drive down those is a good thing. But then you have assholes taking the work of others and then selling them for profit without permission. There is a weird line between the two for sure. But for me it is pretty simple, if it is no longer being commercially produced, or if the original developer has abandoned it completely and/or doesn't give a crap then it is fine to resell / reproduce.
On the other hand when some homebrew is made and people just throw your work out there so they can profit on it, even if you didn't intend on profitting yourself, I can totally see why you would stop releasing roms. It is a shame that a feww ass goblins have to ruin it for everyone else.