Remember that the only reason why we have "The Amazing Spider-Man" and it's sequels is because of the falling out that Sam Rami had with Avi Arad and Sony Pictures. There's a reason why "Spider-Man 4" was cancelled and it was due to Rami being pissed off at the constant interference and suggestions from Arad, he wasn't able to just work and film the movie he wanted to make. It is also the reason why "Spider-Man 3" was flawed as well. I'm beginning to think the same thing happened with Marc Webb as well to a degree.
I don't see Spider-Man going back to Marvel Studios any time soon. It is possible for Sony to sell them back the rights, but I have read in the past that this would be in the billions of dollars rage, and even though Disney/Marvel has a boat load of cash I dunno if they'd be willing to spend that much. Who knows though.