Why do characters from Marvel Universe have muscular physique most of the time?

From all comics I have read, characters from Marvel and DC universe are shown to have a generic muscular built. Usually male characters have similar muscular structures only to vary in size. By generic structure, I mean, male characters have broad shoulders pumped up chest and biceps, ripped abs and so on. Also female characters have generic physique with slender torso, slim hands and so on.

I know there are many main characters who don't fall under this category, characters like, Quicksilver, Blob, Kingpin and so on. Some characters don't have buffed up physique because of certain disability or condition (Charles Xavier).

I know there will be many more characters who will not fall under perfect physique (and many people will start lynching me with their details), but from whatever I have read or seen, most of the superheroes have it.

I mean in reality, if soldiers or sports personalities are to be considered, they are strong and hyper active. But many of them don't have perfect physique. Even thin once have strength while strong ones have somewhat more strength.

My point is Cyclops can be of normal physique, while he can still shoot lasers and defeat enemies. Wolverine needs good physique as he has to fight using raw strength even while using claws.