The licensing talk in here is hilarious.
So, to summarize:
Marvel owns the character itself.
Sony optioned off the film rights to Spider-Man decades ago, and Sony has held on to them for the longest.
Marvel retains licensing/merchandise rights for the character in non-movie situations, explaining how so many many publishers have been able to put out games with Spider-Man in them.
What's interesting is that there's the possibility that Sony's deal for the Insomniac games could just be for platform exclusive games. It doesn't happen often, but it happens sometimes. The last time something like that happened was when 2K had an exclusive deal with MLB to be the only publisher of multi platform MLB games, and Sony loopholes them to be able to make The Show, under the stipulation that it be exclusive to Sony platforms.
It's not outside the realm of possibility that Marvel (Disney, really, let's not act like we don't know who's really calling the shots) cut the same type of deal to leave the window open for games like The Avengers to get him in as a group member.
But then Sony came through with ANOTHER bag, so.....