I think it’s more that it’s been shown that a motor at each panel is more expensive than manually rotatable mirrors that are maintained by a smaller set of mirrors. For example, there was a startup a few years back that had robots on a rail system go to each panel and adjust it.

The reason should be obvious in that the motors are higher maintenance systems so you don’t want to scale with the size of your plant. I imagine drones are being used for a similar purpose: the drones further reduce how many adjusters you need vs rails and the AI is so that the drones can actually adjust the panels.