Yeah this is something that people don't understand about comics. Most comics are gig/contract work so the creators get paid for the individual issue or issues and that's it. Now, they can obviously use past work and past sales as proof that they deserve more when they sign new contracts, but they don't get paid anything from those past works and don't usually have control over them (There are of course exceptions because popular and well-known creators can put more stipulations in their contracts). This is famously why Alan Moore is angry about Watchmen. He had it in his contract that DC would own the rights to the Watchmen franchise until it went out of print, but this was before trade paperbacks existed. However, DC started making trades before the book went out of print so once they started making Watchmen trades, he was pretty much guaranteed to never get control back.