This is such a weird statement in so many levels.

The latent assumption here is that learning is zero sum.

That you can take a 30 year old from 1856 bring them into present day and they will learn whatever subject as fast as a present day 20 year old.

That teachers doesn't matter.

That engagement doesn't matter.

Learning is not zero sum. Some cultural background makes learning easier, some mentoring makes is easier, and some techniques increases engagement in ways that increase learning speed.