Of course, their suit is about residuals for past work performed by this actor. They should know not to cross him, even in death!
Maybe one day the unions will be able to negotiate that all income for all shows goes into a common escrow pot. From that account, revenue and expenses would be distributed equitably, according to a given plan administered by an independent fiduciary. As any accountant should know, debits and credits are supposed to balance. Another way to say this is that goods and services equal money, and money equals goods and services, the amounts fixed by governing contracts.
However, let no man or woman hold their breath. The producers maintain a stranglehold on this possibility, and the unions seem to be powerless to change it. Guess they retain better lawyers.