Flipped learning models suck unless they're done perfectly. And 90% of the time they won't be done perfectly.

In my experience (as a student), what actually ends up happening is that students don't do the lectures, which leads to low engagement with the classwork. This also tends to punish people who fall behind, since class time is useless without doing the prerequisite material.

On the flip side, your ability to do homework with the teacher is limited by class size, which have to be large unless you can find a large supply of teachers and buildings to put them in. So what ends up happening is that you teach yourself, which is great if you're smart or talented enough to do that. But if you're not, it's very easy to fall behind and stay behind with this model.