When the state gets to set the tests, the state controls what gets taught. Until the last 130 years the federal and state governments had virtually no role in controlling curriculum. When there was no government involvement - say 1800 - Americans were more literate than they are today.
Government destroys almost everything it touches outside of national defense. Why do we have this superstitious belief that “government” (politicians and bureaucrats)make things better? What evidence do we have for this? The EPA? Social Security? The Post Office? Energy policy?
Government has controlled public education since Jefferson. That being said, for a virtual curriculum market to exist, it has to be limited to just students, their parents, and experts to provide content. Not government bureaucrats, pedophiles, marketers, politicals, or other such scoundrels.
So I gave the wrong impression, that this would be a government project. In fact, the government input would be like that of market regulation, much like it is when a better government regulates home schooling, to insure that it is not misused to deny education, and achieves at least minimal standards—while not inhibiting its doing much better than that.
And yes, there are plenty of bad government stories from home schooling advocates. But also plenty of times when they worked with government to achieve a good educational and legal environment, that was at least tolerable.
It is important to mention the value of such a system, where today there is no system. Transient students, students who become ill for an extended time, students with other problems, can lose years of education because there is nothing for them outside what exists right now.
Add to that that education for most students is very dependent on their relationship with their teachers. Invariably there will be good teachers and good students with poor chemistry between them for nobody’s fault, that learning just doesn’t take place. For there to be some, any alternative, by which the student can learn the material is essential that an opportunity isn’t lost.