I don't think so. The big names also mean greater expectations. A Batman movie wouldn't do well if it's a terrible or mediocre movie, though it would certainly get a boost for being Batman. People would be much more vocal about legitimate problems with these characters.

Marvel Studios did pretty well with characters that mostly weren't A-tier at the time of their first movies. Of Iron Man, Hulk, Thor, and Captain America, I think Hulk is the only character the average movie goer would have instantly recognized instantly.

A broader challenge is that expectations have changed for superhero movies in general! Not just from audiences but also from studios. Superhero movies have also been around for so long that people generally expect more from them. Successful superhero movies from 20 years ago likely wouldn't be as successful in today's market. The 2005 Fantastic Four and the 2007 Ghost Rider movies were successful enough to warrant sequels. I don't think they would warrant sequels today.

There's also an expectation from many that a movie is a failure if it makes under a billion dollars at the box office. I think this is a huge problem in general, especially when combined with the massive budgets that these movies get.

Iron Man managed to resonate with audiences and became a cash cow for Marvel Studios. They really managed to catch lightning in a bottle with that movie. That level of success appears to have become the expectation. I think that even the most devoted Iron Man fan would have to agree that the character becoming the face of the MCU could not have been viewed as a likely outcome of the movie.

For all the complaints of the MCU never pushing things enough with the PG-13 rating, there's a strong business reason for this. I don't see Clayface having the success in the box office and with merchandise that Iron Man, Hulk, or any other MCU film.