I mean, it's just as likely that they ended KoX early because when they finally got corporate approval for the Betsy/Rachel kiss, they saw an opportunity to rebrand the book in a way to leverage that angle for better publicity. Series that get cancelled for bad sales tend to just... end.
Immortal Hulk is pretty much the only Marvel book of the last decade to sell well enough to avoid the pressure of relaunches to goose sales. It's not really a black mark to get relaunched, as much as people on forums disdain the practice.