He sells Milfy City to others: he loses his patrons, which means he loses his income.
He pays fee or splits the income with someone: he still loses money.
Icstor is all about money these days, and people are paying him only because of Milfy City. No Milfy City means no supporters, no supporters means no income. That's why he is delaying this situation with Milfy City, because he knows that as soon as he is done with it, people will scram off from his Patreon because they couldn't care less about his other projects anymore, especially when the "complete" version would be far from complete, so he has to milk as much money as he possibly can before he has to pull the trigger.