To be more precise, those mid-budget films all did well relative to their budgets. Marvels still made far more money, but the budget was so bloated that Marvel took a loss.
They lost at the box office, but reviews for The Marvels suggest it's the better movie (although not by much). That's even taking into account the fact that horror tends to get worse reviews as a genre. There are a lot of reasons why The Marvels might have performed so much worse in ticket sales (I'm guessing superhero fatigue, and the character(s) not being very popular to begin with had a lot to do with it), but Disney's MCU can recover as long as they're willing to put more effort into giving people a story worth watching. The NYT's review was titled: "You’ve Seen This Movie 32 Times Before"
The Marvels: $197,035,186
That's how badly Marvel movies are bombing now. FNaF actually straight-up beat Marvel, and by a very comfortable margin.
There is no minimizing this. This is disastrous for Disney.