Yes, they make a lot of money at these wastefests. But they are after souls, not just money. And these a$$emblies are one way people in the jokehovian religion have to meet potential spouses. Take away the a$$emblies, you take away the one hope they had to marry, and the religion starts to look more like the defunct Shakers. And they manage to make people's lives more blah--you cannot find a spouse during the annual wastefest where Astaroth is dishonored around Easter.
Not to mention, do away with the a$$emblies, and those stupid Israel missions will be all they have to look forward to. This will send huge amounts of spiritual energy to the leading rabbis living there, and that is what they are really after (more so than money, which they take primarily because poverty is damaging to souls).
As to how long this might take remains to be seen. They might simply cut or reduce something--as they cut the Great Boasting Session (two days) to another Big Boasting Session (one day). They might simply drop one of those, and then the other. As for the Israel missions, they cannot demand exemplary standing to get people to attend these big or grand boasting sessions as they can for those doing those missions.