If Marvel owned the rights to all their properties... shiiiit Scarlett Johansson would probably be Jean Grey, and Black Widow would likely be Agents of Shield status lol... maybe Netflix. There would literally be no need for Captain Marvel either b/c the X-Women would fill in all those needs.
Spider-Man, X-Men, the Fantastic Four (if only because of Doom, Galactus, Silver Surfer, etc) would be at the fore front.. and while you would still have Iron Man, Captain America and Hulk involved, the Avengers as a brand would be radically different... either in importance or team members.