Help me understand why not? I know solar power generation in space, and "beaming" the power back, was a naive idea. But this would actually use the power up there, mostly for training, but also for inference.

That claim seems reasonable. I have zero knowledge of the economics of launching and maintaining satellites though.

As I understand it, the problem is cooling. There isn't any medium to take away the heat, so the only option is to slowly radiate it away.