The last of these recent years’ superhero movies I saw had the protagonist fly from the ground on earth into space and fly through a fleet of supposedly extremely advanced and capable and enormous spaceships in order to win the fight. Literally, simply flying through as if playing a connect the dots game.

One was left wondering how there could be any further movies with this person available to fly through anything.

They are typically just written out of the conflict. In this case I assume that you are talking about Captain Marvel whom I believe is always needed on other planets in other galaxies except for the rare occassion when the writers needs a deus ex machina.

Same for the Green Lantern Corps. They are always needed but there's far too few of them so 99.999% of the time the heroes in these stories kind of hold the front until a GL shows up and beats the threat relatively easily.

I quite enjoyed that universe for a bit of time but the ever-inflating (and absurd) power levels and lack of actual stakes eventually ruined it for me. As it did with most mainstream superhero movies.

I think the term for this is power creep and it also applies to games