My intent is not to diminish Thor. It is just to remind of context. Even the example you gave is about significant odds. We usually judge this sort of thing in that context.
Your are right that the ability to fight through despite all of that is key. However, I would still argue that this is more an exercise to play up lower tier characters than to diminish more powerful ones. They have to push harder in general that the more top tier guys in each situation.
Of course all superheroes have that gut check moment, some have many if they have been around in comics long enough.
I am just trying to explain my thoughts on what is meant. I do not think it is a knock on Thor, Superman or whomever else. It is more a matter of admiring the determination to heroes that may not even have powers in the first place.
applies regardless of 'level'. Lower level characters have more opportunities to showcase the ability, but aren't necessarily higher on the scale.
Mockingbird, for instance, in Emperor Doom, didn't have the willpower to resist Purple Man's influence...she didn't have the will to fight it or the mental fortitude....she's nowhere near top tier in that regard.