While this is true, the same logic would apply if they had an easy mode. “If the game on easy is no challenge, then leave it on the default difficulty.” Just make it so you have to intentionally pick easy mode at the start and disallow changes on that run.

Now don’t get me wrong, I’m not so naive as to think adding an easy mode would be a free, no effort thing. It would absolutely add work for the devs. But I think, probably not that much. And a bunch more people would buy the game. It’d be totally worth it for them, I suspect.