I read an article, I forget where, that talked about Marvel's moves in movies and tv. The gist of it was the movie people(including producers) want nothing to do with the tv side, they would rather there wasn't a tv side of things to begin with. Meanwhile, the tv actors are desperately hoping to be brought into the movie side. Disney and Marvel of course would like to rake in every dollar they can, so that's why there is a tv portion of what they are doing.
So it occurred to me, if I'm Disney/Marvel I need to start thinking about picking my cast among actors who'd be willing to play the characters on tv or in the movies. That's how you could generate symbiotic crossover events. Instead of the Marvel Cinematic Universe it could be the Marvel Live Action Universe. Instead of signing actors for X appearances as Iron Man, maybe sign them for X years, any amount of appearances in any medium. Maybe say you have to give them a year's advance notice for tv appearances and maybe limit their time on set to a minimal amount, like one day for the tv shows. Maybe around Phase IV they can try something like that.