Spider-Man is probably a bad example: he became Marvel's #1 guy from his Day One because of how he was designed from the start: he is supposed to lose way more often than the typical superhero. He can't get a win without suffering some kind of loss elsewhere. That is what the original appeal of Peter was. He bats .500 in life.
Spider-Man is uniquely positioned to take a constant beating and still hold on to his popularity.
The better example for Marvel is probably Wolverine. How many times has the Hulk jobbed to him to make Logan look more badass than he is?