I'd guess escorting is her main income source, and while she might make money shooting on the side, it's not enough that it should be her primary moneymaker. Given that, I can see the logic in being comfortable with one guy who's safe, reliable, fair in terms of splitting money, and presumably doesn't have trash dick. Other collabs might not be worth risking in case one or more of those other factors aren't satisfied.
I think it's fine, they make good vids together. She has the opposite problem of someone like Nickitheboss, likewise amazing body who sticks to one guy but the content is not as good as it could be.