It seems to me that this Prussian model system isn't really even intended to educate so much as it is to school. I think the difference is important. Our Prussian system was designed to output workers (schooled), not creators (educated).
Consider that many of our great creators throughout the last couple hundred years that the our current school system has existed have been early dropouts.
I think you are spot on about critical thinking. I don't know why that isn't the root of all learning. Many of the great ancient philosophers studied the Trivium. Why isn't that even known about today?
We are about to see a huge shift. There are so many opportunities opening up every single day on this beautiful sharing economy that is now a thing.
A person can learn pretty much anything at any time from the teacher of their choice these days. A lot of it is free, some of it not.
The big question in my mind is going to be how those parents that need a baby sitter for their kids are going to figure it out. I'm sure that the market will provide.