While a 50/50 split is a bit much, that’s where negotiations should have started, not just burning the whole thing to the ground. They just made a billion dollar movie, something that they had never managed before and, even with the success of Venom, hadn’t matched with any of their Spider-Man based movies. There is no doubt that at least some portion of that came from the fact that this was part of the MCU. Without that, who knows what level of success they’ll see. It screams cutting off your nose to spite your face.