Eh, all the guys on the bottom are superheroes so their strength comes from superpowers (or in the case of Tony Stark, technology). A better 80s comparison would be Michael Keaton as Batman and he wasn't ripped by any means.

It doesn't seem like there's many muscle action movies these days, true (although I don't keep that up to date with current mass appeal films). But there's still some ripped dudes out there. Henry Cavill comes to mind.