A new interview from Portuguese language website Super Interessante has been making the rounds on the intertubes, most notably for a quote from Avengers: Infinity War director Anthony Russo about why the characters from Marvel's TV and Netflix shows probably won't appear in the film:
It's complicated. When we start to serialize the telling of stories is difficult. You have to have a lot of control and focus on the course of history. The films are controlled by a group led by Kevin Feige, so they function as a unit. Other products, even if they are from Marvel, are controlled by others. Then there is the possibility of a crossover, but is more complicated. It is a smaller version of the problem that exists when thinking that Fox has the rights to certain characters, Sony and others. As storytellers, we only have control over what happens in Marvel movies, but everything is possible, the spider (which has the right held by Fox) was possible!
The complication Russo is referring to is the blood feud between Marvel Studios head Kevin Feige and Marvel CEO Ike Perlmutter, which has led to much rumor and speculation. The pair of powerful corporate executives have been battling since the Marvel Creative Committee had its control over Marvel's movies removed earlier this year, leading to speculation about a canceled Inhumans movie, a canceled Iron Fist TV show, and a budding romance between Perlmutter and former enemy, Bleeding Cool rumormonger Rich Johnston.
Later in the interview, Russo revealed that Kevin Feige keeps a dartboard with Perlmutter's face on it in his office, while Perlmutter has been known to pull out his gun (not a euphemism) and shoot any television set playing a Marvel movie at Marvel's corporate headquarters. It's one big mess, but at least it's not a hundred year old law keeping the shared universe from actually being shared, like in the case of DC's Supergirl and Arrow properties.