Part of the difficulty becomes when a system is so long-lived; the Dolphin project for GameCube and Wii is highly valuable, worthwhile, and good even if some (perhaps massive?) percentage of the people using it pirate games that are no longer sold.
Nintendo is also in the business of rereleasing games were no longer sold.
Also, ~70% of game sales are within the first month, if not higher. It’s why companies pay big for Denuvo - slowing pirates down a month could save tens of millions. For Nintendo, having games dumped before release is embarrassing and at the worst possible time financially for both them and their developer partners.
If we were talking about Switch game dumping after the end of the Switch’s life like the Wii or GameCube it would be a very different discussion.