Years ago, I did some work on thermal management of small satellites, mostly for cooling higher-power onboard computers. The scale is different, but the physics are the same.

The story of SpaceX is often that Musk tried to buy a rocket, got a price estimate, and did some first-principles evaluation of the materials and engineering costs he believed was involved that came out to be much less than the going price. He ended up (through fast-forward view doing a lot of work) being largely correct.

The data-centers-in-space in space thing does not work out from a first principles approach. The waste heat generated by chips and the cooling method available (ultimately, radiative cooling), and the structures required create those surfaces, would be orders-of-magnitude beyond what could reasonably compete with a terrestrial version with the same capacity. There's no "but launch costs are dropping" adjustment that can possibly make up for that. The physics involved are the blocker.

Starlink is actually a good counter-example of where the execution--building and coordinating satellites in volume--was the bottleneck, not the underlying physics of the networking and SpaceX was in a great position to capitalize with their engineering expertise and reduced launch costs. It's a totally different situation for the data center thing, though.

There are some unusual but otherwise plausible ways to reject heat at incredible scale without involving a lot of mass.

https://en.wikipedia.org/wiki/Liquid_droplet_radiator

Space has many downsides, but it also comes with a few advantages.