Most of the casks that disappeared from Homebrew in the last couple of years didn’t go because the software was bad. They went because the author hadn’t paid Apple.

That’s not how anyone phrases it. The PR says the cask failed brew audit. The audit says the binary is unsigned, or signed but not notarised, or signed by a Developer ID that doesn’t match the bundle. The deprecation policy gives the cask a sunset date. From the outside the chain looks like quality control. From the maintainer’s side it’s a $99-a-year invoice from Cupertino.