> The only one that might apply is cost: if it's cheaper to build data centers on Earth, then space doesn't make sense (and it won't happen).
So the only problem left to be solved is that space datacenters would be millions of times more expensive per unit of compute than a ground based datacenter. And cost millions of times more to maintain.
Starlink solar panels generate at best 200 W/sqm on average. Even with 2.5 million square metres, that is a total of half a gigawatt. And the cost is not to be ignored! Most of the cost of these data centres is in the GPUs themselves, so you need to add that to the cost of building out the constellation. Unless you are arguing that the cost of supporting infrastructure (cooling, power, etc) costs $10bn to support half a gigawatt of GPUs in the typical data centre, then your numbers are simply way off.
Starlink cost maybe $10 billion. A 100,000 gpu data center costs between $20 and $40 billion to build.
Also remember that data centers last for about 5 years; after that the gpus are obsolete. That’s no different than the lifetime of a Starlink satellite.