Different film studios have even struck deals to work together. Marvel and Sony came to an agreement so that both could use Spider-man. Sony and Fox worked out a deal so that the button scene for The Amazing Spider-man 2 was a teaser for Days of Future Past. With all of this co-operation, and the obvious boatloads of money to be made, I think the time will soon be ripe for the grand daddy of superhero movie franchises to be made.
Back in 1996 there was an unprecedented crossover event. Marvel and DC brought their characters together. This wasn't the first or last time this would happen. But this one was different. You see, this wasn't just a crossover. They took their most popular characters and merged them, creating the Amalgam universe. Instead of Superman meeting Captain America, they were fused into a single character named Super Soldier. We didn't get the inevitable sweaty hero on hero action from Batman meeting Wolverine, we got a dark violent character named Dark Claw.
Now, obviously DC, Sony and Fox would need some time to establish their respective movie universes before something like this could happen on the big screen. But we have seen that studios can and will work together when there is money to be made. And do you really think this wouldn't make money? It's a ready made franchise. You could get half a dozen films out of it easily. Besides Super Soldier and Dark Claw, you have Dr. Strangefate, Challengers of the Fantastic, Amazon, and Speed Demon. Oh and Lobo the Duck. Tell me you don't want to see that.
With all the division between Marvel and DC fanboys, these would be movies that everyone could get behind. The only problem I would see with these movies is that four movie studios would have all the money and the rest of the world would be bankrupt. I know that a live action Amalgam franchise isn't likely, but I would have said the same about Suicide Squad or Guardians of the Galaxy not long ago as well. I remember thinking we'd never see Spider-man on screen with Captain America, and that has happened. At the very least a series of animated features should be made. Do it for the children. (And the grown ups who are still children at heart.)