Why the music in Marvel movies is so forgettable

I never really thought about this, but it's so true. When it comes to Marvel movies, these huge blockbusters that rake in millions of dollars across several film franchises, there's not a single theme song that I can hum back if I were asked to. It's weird especially when I am able to hum the tunes of other equally big blockbusters. Why is this? Every Frame A Painting says this is mainly because of recent trends in movie film scores where the music is made to not be noticed. Odd since I tend to think music often plays a HUGE role in manipulating how one feels when watching a motion picture. And the lack of recognizable music isn't due to laziness, it kind of has to do with the use of what's called "temp music" during the production of a film in general. Sometimes, composers who listen to temp music get roped in to one particular sound I guess.