Yeah, well, college faculty do it, too. I'm not saying it cannot be done. I know that it can. I've taught classes of 200+ students.

But there are a lot more things to consider in secondary and post-secondary, too-- development supports better executive function in students, better metacognition, etc. All of those things require very different methods in primary and the first years of secondary. It's an arc.

Schrödinger's cat walks into a bar. And doesn't.