But what if we just don't agree with either premise?
Many people are aware that there are already superhero RPGs out there, and if they wanted to play the Avengers, they would play one of those RPGs, not D&D.
DnD
is a game of Mythic heroes. The rules (and expectations of the game, as evidenced in all settings and adventures) reflect this.
If you dont agree with that premise, cap your campaigns at 3rd level, or use different rules.
In DnD, from mid to high level onwards the characters are expected to fight (and defeat) T-Rexes, creatures that can fire disintegration rays, psionic creatures that can control thoughts and eat brains, armies of Giants, fire breathing dragons, undead reality altering near immortal Liches, literal demi-gods and demon princes. They travel the planes of existence, alter reality with a word, teleport to other continents, call on divine intervention, can be doused in magma or fall from a 30 story skyscraper and survive. They raise the dead, load and fire a crossbow 8 times in 6 seconds, slap great white sharks to death, get so angry they can fly, consort with elder powers, use magic, create AI, grow wings, etc etc etc etc
They are the X-Men or the Avengers.
Aragorn runs away from a Balrog. DnD characters stab it to death with pointy things and take its boots.