According to Feige, Marvel had “a very particular plan about Spidey himself” and not those supporting characters.
That’s after his starring turn in Spider-Man: Homecoming and 2018’s Avengers: Infinity War.” And there’s also a Spider-Man: Homecoming sequel in the offing as well.
Just last night I saw Guardians of the Galaxy Vol. 2, and sure enough it concludes with the words “The Guardians of the Galaxy Will Return.”
That plan, I’m going to assume, went something like “Get Spider-Man in Avengers and make lots of money.”