That makes no sense to me. You've cited one overhead for building on land but just didn't bring up the billions of overheads for deploying satellites. The associated costs of launching this stuff into space blows the price of boring old power grid infrastructure out of the water, even with launch prices assumed to be the cheapest they can be. For instance, the extreme additional costs of equipping each payload with their individual systems of power generation, flight computers, maneuvering systems, structural components, communications infrastructure, heat dissipation hardware, radiation shielding and so much more. You have to pay the price in weight and money for all of these inefficient small-scale components for each unit launch, compared to plugging in an additional server rack and taking advantage of the economies of scale in a centralized data center that already solve all of these things. And that's before you get into the costs of designing, mass-producing and operating these things, compared to the costs of running a normal data center. And that thing about reusability that I mentioned also cuts into the margins. Data centers can keep working even if their hardware is a generation out of date, they can sell off old equipment, they can repair individual components instead of throwing out a whole rack. This is literally setting your GPUs on fire. It's just one more thing that makes it even more expensive.

Heat dissipation in space is possible, of course, but every kilogram you spend on heat is a kilogram you could've spent on something else. When you're talking about boxes that generate so much heat, you're going to need to spend a lot on that ancillary hardware in each unit that, again, makes it even less rational.

Then the concerns about megastructures or distributed computing go unanswered - to my knowledge, we simply don't have the technology for either of these right now. Starlink isn't close to solving it - the bandwidth of a Starlink satellite is nothing in comparison to the bandwidth of a single current-gen server GPU connection.