Here's a fact: Marvel has had many, many crossover events over the past few decades. Some of them are.... forgettable, is the nicest way anyone can put it. Some of them, however, are as iconic as any superhero or story arc, with crossovers such as Civil War making their way into the public consciousness through film and TV.
While many titles and events have already been depicted on the big screen, some with the same name, like Age of Ultron, and some having their major elements pulled for other blockbusters, such as Planet Hulk in Thor: Ragnarok, there are still quite a few status quo changing incidents in the Marvel comics universe that haven't found new life in Disney's biggest moneymaker and Hollywood's blockbuster darling, the MCU.
And while they won't always fit into the MCU's current canon, ten years in the making, it seems like the recent Disney-Fox merger and rumours of time travel and multiverse shenanigans will open up new possibilities for the biggest name in Hollywood for the next few, let's say, decades.
Luckily for them, they have lots of memorable, interesting, and adaptable titles they can draw from...