Don't get me wrong - there are massive hurdles for something like this. To get a footprint large enough to compute at scale, a huge amount of satellites would be required. They would all need to be large - solar arrays for power, as was previously mentioned, and the radiator for cooling. That means the space reservation for the orbit would be massive...and i'm not sure it exists. Then add in the costs to launch them all. Much larger than the starlink clusters, the rocket would need to be re-worked for a larger payload (i think), and the fuel costs would be enormous. Lastly, they'd have to do it at a regular interval to continually replace the failing hardware as @morbro correctly points out, the toll the hardware would take out of the atmosphere would degrade things quickly. So ... not an easy problem at all, but power isn't the limiting factor.