>>212254436They already did this exact arc in the 2005 film.
>>212256055It's not necessarily self-sustaining, but at its core the future of the franchise is more a situation that it needs repeated flops/bombs to kill it. We're off to a good start in that regard.
Cap 4, Thunderbolts and Fantastic Four were supposed to introduce over half the cast of Avengers Doomsday. With Cap 4 and Thunderbolts being a disaster they've now changed the X-Men from a cameo opening battle in Doomsday to having a larger role in the hopes it generates interest. Originally they were going to show up for the opening of Doomsday and then have a larger role in Secret Wars - now it's kinda flipped around with a larger role in Doomsday and showing up for the final battle of Secret Wars.
If Avengers Doomsday/Secret Wars under-perform, given the budgets for either film are $500m+, then Disney will be forced to scale back or lower costs on future Marvel movies. Though they already intend for Secret Wars to function as a reboot, ending with a multiverse reset featuring the reintroduction of older characters played by new actors such as a new T'Challa Black Panther and a new Tony Stark Iron Man who they are not going to reveal the identity of but are considering having Tom Holland play the new Tony Stark once the Sony deal ends.