I think the author knows and is assuming a lot of what you're pointing out. The technology for the Primer as such isn't there and won't be until we have general

I think the author knows and is assuming a lot of what you're pointing out. The technology for the Primer as such isn't there and won't be until we have general AI. However, we could build something today with current tech, like a Kindle that teaches you to read, or teaches you calculus, and it wouldn't be hard to make a compelling product. There are many possible starting points and the technology isn't really the problem if the goal is just to make a start. The real problem is much deeper and the key point is that the Primer was subversive. How do you organize a consumer product company around a subversive product? You don't. So how do you fund such a project? These are much bigger than the technical problems. There's a reason why Stephenson had the Primer commissioned by an infinitely rich eccentric and built by a rebel engineer. What I suspect the author is hinting at by talking about data isn't that the data is hard to get, it is that for any company in our society with access to that level of resources to start making machines to mold young minds would be a pretty short road to a pretty boring dystopia.