The difficulty here being the facilitating and behaviour management, which is exactly where the teaching degree comes in.
It really isn't an easy job. Facilitating the individual learning and pace for each student alone is a nightmare; some students take an hour to figue out something that others get in 5mins. Can you imagine helping out 25 or more individuals, all in a different context due to completely different paces? There is a skill to that. It's the reason schools generally stream classes, and also the reason for set points in a lesson to move to the next stage, which is at teacher discretion in some places at least, so as to gauge the next steps to take with the whole class.
As for behaviour management, this assumes children passively sit there and are ready to learn. That doesn't happen. Children would get up, push the on/off buttons of their neighbours' tablets, make animal noises (a new favourite in my Y11(!) class), throw pens, figure out a way to circumvent the restrictions to play online games and get up to any number of distraction measures to avoid work. A reason why most schools ban phones, have tight computer controls and now increasingly punitive behaviour management policies. Many children cannot be excluded under safeguarding concerns (as they would be worse off at home than in school, how sad is that).
And since children must not be allowed to fail by merit of their own unwillingness to work, who would be held responsible for progress?
No, the system needs an overhaul, but we're a very long way away from the scenario you envision.