[quote=@Kafka Komedy]
Hm. Yeah, I guess just not really worrying over the reason is an option. Really it's all about what kind of story is being told. Just about a group of super heroes? Who cares about a reason! Want an over-arching villain? Well, having that massive universal collide would be a reason for all the heroes to fight someone all-powerful.
[/quote]

I think I would prefer the futility of being stuck dealing with a world that is not quite their own and have to deal with the situation. Because that would be a big deal.