I think that's what led to Miles, actually. Ultimate Peter died, and some other kid took his place. He's apearently popular.
Really? According to
this: "Despite the early excitement, Ultimate Comics: Spider-Man is not a huge hit in the direct market."
The writer goes on to make an "affirmative action" argument that Miles should be kept but, if anything, that undercuts the notion that Miles is "quite popular." Were that the case, the affirmative action argument would seem unnecessary.