Note that this is different in gaming than film because of technical progression. But also Nintendo are very good at "same charm, familiar characters and plot, different feel".
But they don't simply do roster updates, they bring those characters and worlds into new experiences, and they're willing to sit on good games rather than push out yearly new releases with almost nothing different compared to the previous iteration.
And the stability these franchises gives them, allows them to continue to make new IPs that may themselves grow into future tentpoles. So it's not just that they squander those successes, they are often trying to innovate into new things.
Disney + Marvel offers a roadmap for extending existing IP. (Keep in mind that the Marvel acquisition was in 2009.)
The usual tricks of "noise signals how many are really upset in absolute terms, not the relative popularity", "people will still make noise about what they don't like regardless if that's more popular overall", and "people who hate one attribute of the product can often still like it enough to buy overall".