to be fair to the cartoonishly greedy and parsimonious movie studios...
the whole economic model of the movie business has changed vastly over just even the last few years. The collapse of the physical media market changed the equation big time, and streaming services and on-demand viewing haven't yet even come close to closing that gap, let alone making up for that lost revenue.
Also, some legacy titles do in fact earn substantial sums, but most don't. Yeah, some beloved film like Demolition Man still gets TV play and Blu-Ray sales decades after the fact, but can the Richard Gere and Hulk Hogan movies it curb-stomped on its opening weekend (Mr. Jones and Mr. Nanny, respectively) say the same? For a lot of movies, if they don't earn bank within their first year, their value drops precipitously over time and never gets better. Note that Sly isn't suing anybody for the eventual profits of Stop or my Mom Will Shoot!.
A fairer, more transparent economic process would actually benefit everyone. Artists, technicians, and yes even the studios (in the long run at least I think it would). But its not that crazy to think that a great number of films actually aren't that profitable.