Originally Posted by Shikamaru
I wouldn't say he's difficult or that he can't be popular (since he is), but I think he has two major disadvantages of today's age.
1) Generally speaking, magic is seen as less interesting than science. The more advanced humanity becomes, the more this becomes the case. Another way of putting it is that the more we find out about how complex the science of our universe is, the more we get that "wow cool" magical factor from science that we used to get from magic in the past.
2) We live in the era where intellect is seen as a person's most prized possession. We no longer judge superheroes based on what powers they have, but mainly on the intellect they have. Currently the three most popular superheroes are Batman, Spider-Man, and Iron Man. All three are consistently portrayed as characters whose intelligence are their greatest weapon. Due to this, characters whose intelligence aren't as shown/downplayed are harder to sell and have it harder to produce box office money than other characters. In the case of the Avengers, Thor has the least intellect shown out of the Main 4 (Tony is a tech genius, Cap is a natural leader + tactical mastermind, Bruce Banner is a brilliant gamma-radiation scientist). Although this doesn't mean Thor can't be successful, his chances of his popularity reaching Batman/Spider-Man/Iron Man levels are very low, especially in comparison to the other Avengers.
Marvel doesn't clearly define Thors world as a magical one.
They try to have it both ways with the idea that the Asgardians are an advanced race that uses science that looks like magic .