One thing we have to do as teachers, is that we have to engage our learners. I don't think that sending them off to watch a video does that.
I've had to take a bunch of online courses with videos. I zone out on them unless they are really short and really dynamic. Even videos that show me how to do something I want to do. I usually end up fast forwarding to the part I don't get and skipping the rest.
If I, an advanced learner who is dedicated to learning, zones out, why does our average un-invested learner do? Or worse yet, our limited English speaker (and listener do?) I bet they don't even turn them on.
Even if you have them do it in the classroom, how does that substitute for a teacher who cares about them in their face?
The answer is to reduce class sizes and get more teachers in the classroom who care. Oh yeah, that's a problem too.