There is practically infinite land in which to build a datacenter.

The math literally works.

The US mandates by law that we grow a fuck ton of corn to mix 10% ethanol into gasoline.

If you replaced just those cornfields with solar/wind, they would power the entire USA and a 100% electric vehicle fleet. That includes the fact that they are in the corn belt with less than ideal sun conditions.

We aren’t even talking about any farmland that produces actual food or necessary goods, just ethanol as a farm subsidy program.

The US is already horrendously bad at land use. There’s plenty of land. There’s plenty of ability to build more grid capacity.

Only if you also disregard all the negatives.

The panels suffer radiation damage they don't suffer on Earth. If this is e.g. the same altitude orbits as Starlink, then the satellites they're attached to burn up after around tenth of their ground-rated lifetimes. If they're a little higher, then they're in the Van Allen belts and have a much higher radiation dose. If they're a lot higher, the energy cost to launch is way more.

If you could build any of this on the moon, that would be great; right now, I've heard of no detailed plans to do more with moon rock than use it as aggregate for something else, which means everyone is about as far from making either a PV or compute factory out of moon rock as the residents of North Sentinel Island are.

OK, perhaps that's a little unfair, we do actually know what the moon is made of and they don't, but it's a really big research project just to figure out how to make anything there right now, let alone making a factory that could make them cost-competitive with launching from Earth despite the huge cost of launching from Earth.