That argument doesn't make sense at all, and people keep skipping over the reasons why Sony wouldn't moneyhat a MvC4.
Lots of time and money to spend on negociating the IPs (that Disney would decide, as well as having a say over development), wasting money on an exclusivity when they're already the fighting game console by default this gen, all three studios having different priorities (Sony got already its big fighting IP and big Marvel IP exclusive games, Capcom can't develop games like they did before and have yet to make SFV a commercial success, Disney making tons more by going multiplatform and mobile without crossovers), and various other lesser reasons.