Why would it be a sign they're moving away? They want those two blended. They want a cinematic universe. That's part of how they'll get it. They just had it proved to them that hewing closer to the source pays dividends. They got that firsthand. Here's Kinberg talking about trying to do that with their next crack at bat.
They have a cinematic universe; the X-men universe.
Everything related to Fantastic Four, though, at this point is toxic. Even if they want the Fantastic Four integrated, at this point they have to seriously consider whether including Fantastic Four characters and merging their universe into the X-men would do more harm than good, especially when their X-men universe is still mostly untapped (Savage Lands? Sh'iar? Genosha? Etc.)
And Deadpool succeeded, but we have no knowledge of what message Fox took away from it. It may not be "comic-accuracy pays off"; it may instead be "R-rated movies are popular now. Quick, make the next Wolverine R-rated! Make X-Force R-rated! R-RATED IS THE KEY!"
Maybe far, far into the future, but at this point it's like Deadpool using Green Lantern in their film... as a JOKE. A point of mockery and insult. Acknowledging outright that it sucked and that nobody wants that interpretation anymore.
They're gonna try rehabbing the property because it's worth it to try.
They gave it a try. Then another try. Then yet another try. How many times are they going to try, all while making less and less money? At some point, it becomes less of a "good ol' college try" and more of a "honey, you need to stop. You have a problem. You're tearing this family apart".
Deadpool was a managed risk, but it was still a risk. Suggesting they didn't see it as such is basically a marvel-esque retcon. They risked, and they were rewarded. They're already spending the results of that reward on other projects. Fantastic Four is going to be one of those, because there's inherent worth in the property.
There is NOT "inherent worth" because that "worth" isn't paying off. Nothing has "worth" until you make something WORTHWHILE. Fox has had the Fantastic Four rights for nearly twenty years and produced nothing worthwhile with it, thus their property is, for all intense and purposes right now, worthless. Literally, by definition, it brings about negative amounts of worth. It's actually even worse than that. Worthless would be if it only made its budget back and nothing else, but it instead LOSES money.
They can't even factor in merchandise to off-set the loss either. There's no Fantastic Four action figures, no Fantastic Four video games, no Fantastic Four LEGO sets. And even if they were, the Fantastic Four simply is not THAT POPULAR. It's no Wolverine or Deadpool, even during their peak, either in comics or any other media. They're Marvel's first family, but more people might actually line up for that Gambit movie than another Fantastic Four film.
Again, right now, the whole franchise isn't just unprofitable; it's outright toxic. Doing more with it at this point would be like hunkering down on Halle Berry's Catwoman 2.
That's the problem with arguments about "just give it back to Marvel" - it depends on everyone recognizing there's still worth in the property to some extent. So if we recognize it, why wouldn't Fox? And if Fox recognizes it, why would they just give it back? Especially now that they've been given all this extra slack and rope via the Deadpool receipts?
The "worth" that we see is the Fantastic Four being integrated into a universe we care about. Doctor Doom is cool, but I don't want to see him fight the Fantastic Four again. I don't even want to see him fight the X-men. I want to see him fight THE AVENGERS: Earth's Mightiest Heroes.
I don't want to see Annihilus in Fantastic Four or X-men. I want to see Marvel do Annihilation and have the Guardians of the Galaxy and the Nova Corps throw themselves at the Annihilation wave.
I don't want to see Galactus try and eat Earth again and Fantastic Four involved. I want to see him cruising in space with other Celestials, bumping elbows with Rocket Raccoon and Howard the Duck.
The "value" we see is the Fantastic Four properties integrated with the REST of the MCU, because as cool as Doctor Doom is, he needs worthier opponents than The Human Torch, and as powerful as the Silver Surfer is, he belongs side by side with the likes of cosmic beings like Nova or Thanos.
It's like having a Catwoman film without any ties to Gotham or Batman... The joy of the character is she's part of Batman's universe. Nobody cares about a stand-alone without those elements.
As an expression of fan frustration, "give it back" makes sense. As an actual business suggestion, it doesn't fly.
It makes sense because, at which point do you determine Fantastic Four IS worth it?
You think it still has worth, but to them? They have held on to the IP for nearly two decades and have not made any significant profit off of it. It has lost more and more money over the years with every new attempt. It's a brand that has become outright poison, a source of ridicule and mockery. It's a Razzie Award winner in addition to box office bombs. It's a mismanaged, utter disaster of a franchise in their hands, roundly ignored and criticized by professional critics and the general public. They have had MULTIPLE chances to turn it around, and each and every attempt has done worse than the last.
So at which point does "sell it back" make more sense than "keep pumping millions into a floundering, dying franchise"? I mean, sure, they could pump millions more into the IP endlessly, but... WHY? If there is value to be had in it, they have dug long and hard for DECADES and have no gold to show for it. Just the ridicule and anger of the people who were subjected to their disasters, one after the other.