If the studio fucked off the last time, we would've gotten a good movie. Just hire the same director and use the same intended script but let him do his own thing and we'd get something incredibly interesting.
That being said it's obvious. The f4 is a widely recognizable group of heroes. If Fox can manage to make a Logan, a deadpool, or simply a good movie (90 rt score), they've hit gold.
Why give it to marvel? They'll figure something out and make it successful. That's fox's job
Unlike with other properties, we simply cannot cleanly trace the rights to Fox though. In fact this only gets messier given that Fox and Constantin had been negotiating productions even in the early 90s. Some might remember that there had even been talk of a Silver Surfer movie produced by Constantin and distributed by Fox. None of this would be up for debate if there was a single news about Fox acquiring the rights or if Constantin had announced anything regarding this.
We also know the movies now have to release theatrically for the rights to extend, so it stands to reason the contract was amended, extended, and renegotiated. Constantin still owns some production rights, probably consultation like Marvel, and distribution in Germany and Austria, but that's it I think.
Also, riddle me this. If a minion such as Constantin - who is rumored to want out of the movie business - owned all production rights to FF, why hasn't Disney made an offer they couldn't refuse like they did Paramount in 2010?
1. Constantin doesn't want out of the movie business. There is a really nasty struggle between shareholders about whether or not they should sell the movie division. That's a completely different thing.
2. It's really trivial. They have a deal with Fox. What kind of deal? Who knows. I've seen all sorts of speculation, but neither Fox nor Constantin seem to talk about it.