There is, but you usually have to rely on the gov't being the buyer, and not regular customers. I worked for a EdTech startup (catered to universities) so all our contracts were multi-year affairs paid basically by the government with the unis as an intermediary.
But also keep in mind that the people even getting involved in EdTech generally don't do it for the money, as is the case with Khan. The money my old company was making was pretty crazy, but basically all of it went to various funds and charities and what-not relating to education, because the CEO didn't care about making a buck and likewise with anyone working there.
I wholeheartedly agree with your points about AI though, outside of generating generic quiz questions and stuff like that I think it's a massive net negative on the entire educational system, though I suppose the cat is out of the bag now.