The difference I'm seeing is that Marvel is building their brand while other Studios (Fox) are pushing reboots for the money. Marvel knew from the beginning that Ant-man and Guardians of the Galaxy were 3rd tier characters that had a good chance of losing money, but they pushed them through anyway. People are learning to trust their vision as they move past origin stories. For this reason, I have more faith in Civil War than Apocalypse.
I think it's too easy to lump all Superhero movies into one pile.
Spiderman and Fantastic four were complete cash grabs. On the other hand, DC is trying to straddle both lines. It'll be interesting to see if their need to establish a working universe can overcome their desire to make short-term money.
And no, Superhero movies are not the only films being made, they're just the ones making the most money. The studios have tried with Jupiter Ascending, Tomorrowland, Edge of Tomorrow, Ex Machina, Nightcrawler.... no one cares, even if it's good.