Everybody knows.
Musk is a snake oil salesman (that’s been clear since the self-driving car promises) but he also has made a lot of people a lot of money and that’s all anybody really cares about.
None of his companies have a traditionally reasonable valuation. Is there any reason to think that’s going to change soon?
The reason people don't do it here is because it's too expensive.
But it doesn't matter since in this scenario each chassis is powered exclusively by the respective panel. How hot does a black panel sitting in the midday sun get? That's your equilibrium temperature. As long as it's within the operational limit of the device there's no problem.
The reason earthbound DCs are difficult to cool is because of density. When you match up panels to devices and shelter in their shadow you no longer have anywhere near the same power density.
A datacenter (earthbound or space) itself is a fantastical idea until a mix of events and inventions made it feasible to build them to sell compute.
It’s a engineering challenge not impossible.
After all, it's just an engineering challenge, not impossible.
Now if you have space based manufacturing or fuel production on the other hand ...
Its not a real argument it's just used because to most people the military is a big mysterious thing they don't understand which they think has an infinite budget for things.