It is true they often seem to have a pet millionaire or billionaire, with members like Danny Rand or Dane Whitman.
Then again, the Avengers are that, but even more so. Thor, resources of Asgard. Iron Man, all the moneys. Even Hank and Janet are both well off. T'Challa and Namor are kings. Ditto the X-Men. Warren's got his own company. Xavier's got a mansion, and enough money to buy anything he wants. Ditto Emma, who has had a company and her own college in the past, and still seems to have family money.
And then there are the crazy ones. Lila Cheney has exclusive access to the advanced alien technology and resources of a Dyson Sphere that's basically one giant future-city with the surface area of *six million Earths,* better than anything the Shiar, Skrulls or Kree, put together, could have. Like, just straight past ludicrous speed, right to plaid.