It definitely seems true, in my experience, that one-on-one tutoring achieves educational outcomes far superior to traditional classroom learning. However, I am wary about the ability of technology to scale this up. One-on-one tutoring is more than just providing a customized curriculum and the expertise to answer any questions the student has.

A huge part of learning effectively is developing the right habits. The startups in the article are not really focusing on that, probably because it's the type of thing that people usually learn indirectly through social interactions (e.g. a child emulating their parent). I also believe much of the value of a tutor lies in the social connection with the student, providing them with someone to model their learning habits after as well as someone to keep them focused and motivated.

I think this social aspect of teaching is very hard to capture with technology, sort of like how it's hard to learn a language without living in a country where everyone speaks it. Technology can help, but I feel it will be more like a 0.2 sigma improvement rather than 2 sigma.