In principle I think you are right, but that would mean for each plant you build you need the exact position of each mirror, the oven chamber and the motion of the sun through the day and year. I think the "AI" approach scales better, as it is rather simple "AI" application.
Yeah, depending on the level of precision required, there are _tons_ of variables that could have an impact here. Year to year the angle of the sun changes slightly on any given solar date, as various components of the Earth's orbit "wobble" (axial tilt, eccentricity, precession, etc). Even on an hour by hour basis, thermal expansion could have a significant impact. Any significant structure is going to settle to some extent over time, etc...
I think it's a scale issue, each mirror needs the same apparatus and AI, but doing it traditionally with reactive optics would need a multitude of different pieces?
But also the position of the sun in the sky is not predictable enough to do this completely open loop because of variances in atmospheric refraction... but it's pretty easily measured at the site.
That's just my reading of it, not asserting anything myself.
If every mirror has drifted a small angle, and you're trying to point them all at a very small target-- it's hard.
[1] https://learn.sparkfun.com/tutorials/what-is-gps-rtk/all
That is, with two GPSes, you can measure their vector distance very precisely by correlating their measurements.
But it doesn't help you precisely measure angles, which is a big part of this problem.