Sorry, I tried to be clear that that scenario is an unrealistic ideal. Ideal in the sense of a spherical frictionless student in a vacuum with infinite funding as well as ideal in the sense of good. In that case one solution would be more teachers than students.

Unless/until we figure out a feasible way to make progress not the same pace for everyone, progress will have to be the same pace for everyone.

Colleges have a decent middle ground where if you fail this quarter, there are decent odds your class will be offered again before next year, especially for the earlier classes that really need stricter sequencing. But that’s only really feasible when you have that many students (not to mention tuition $$$).