I mean if you take the Marvel films, it's because interesting stuff is actually happening (to them) all the time. I wonder how many behind-the-scenes shots there are of the actors checking their phones in between shots, lol.

A more general remark would be that nobody in films ever uses the toilet.

They do if it's relevant to the plot. See - Pulp Fiction.

Films really haven't adapted well to the invention of the cellphone, let alone the smartphone. Being able to instantly communicate anywhere ruins so many plots.