There are various factions of Mormons, just like there are multiple factions of Millerites. Ba’hai, Seventh Day Adventist, JW, Bible Students etc are to Millerism what LDS, FLDS, Firstborn, Reorganized etc are for Mormons.
I’m sure the FLDS doesn’t allow their kids to go to college either and they also kick those that don’t accommodate out. But they continue to exist as long as there are girls being born for the leader. The JWs don’t have to moderate as long as there are enough people to fund the lifestyle of the 7.