Because the co-financing part directly correlates to the profit part. From what I understand with how people have explained it, Disney financing half of the movie will entitle them to FAAARRRR more profit share than they are getting with the 5%, and in their mind that is easily worth footing more of the bill. And that would also theoretically entitle them to more control and we all know how disney is when it comes to control, they eventually plan on having all of it. Sony can probably see that bullshyt a mile a way and told them take 10-15 or get out. Disney walked out on they ass.
I say the best compromise is give them 15-20% and cede more leeway to Feige as far as characters and integration goes. Have him help the shyt make sense for the fans sake.
Even if they make this deal, not even on some "marvel stan" shyt, I didn't want a spider-man less spider-verse. You make it so the MCU films can actually do some light weight integration in the same vein as how the netflix shows were supposed to work and Spider-Man 616 () is being the lone Avenger for the time being has a big enough sandbox to have Osborn, Venom, Kraven and Morbius to actually integrate and make sense while still being Sony properties.
Like with Blade, I'd be willing to be Disney asking for more leeway with characters would included using someone like Morbius, how the fukk we "partners" and all of a sudden making competing vampire movies? fukk THAT, a partnership is a partnership. fukk them for being greedy on the money side but when it comes to ensuring Sony doesn't devalue characters that could rock really well in official spider-man outings without breaking continuity, I don't blame Feige/Marvel to try and make sure everything isn't so disjointed and confusing for the fans.
I been going on in on Amy Pascal and it's starting to look like she was the one trying to hold all this shyt together to make amends for those email leaks. Now we have the fukking idiot who destroyed Fantastic 4 and X-men stepping and ruining some more shyt.