SpaceX

Would it not be possible to leverage how cold it is that high up in the atmosphere?

He just does what hundreds of grifters do daily on crowdfunding sites. What dozens of engineering firms do yearly with smooth brain dictators. What tech bros eat, sleep, and breath daily talking to VCs in Silicon Valley. Pitch idiots with cash burning a hole in their pocket to invest in ideas that sound really cool if you don't know how the thing in question actually works in any sufficient detail to do back of the envelope estimates.

He doesn't care about selling or shipping anything. That's not how he makes money. He makes money by getting people to give it to him cash for really cool stories. If he fails to ever sell anything, make any meaningful contribution to society, even do anything at all, none of it matters. Investors eat the bill. Those investors are mostly people's retirement funds running on autopilot, just buying more and more of the 500 biggest companies.

It's solar roadways, autonomous pods, a video game you can do "anything" in, a super app that'll replace all other phone apps, a mars colony, artificial general intelligence, or whatever else sounds cool enough with just enough plausibility to get the money before critical thinking sets in.

Here, the grift is going, well satellites are just computers. We have a bunch of them. That could be a data center. This ignores the need for these systems, both hardware and software, to be radhard against cosmic rays. It ignore the intense thermal swings, the short lifespan, limited frequency space, and the hundreds of other things that just make the cost per kilogram of compute in space prohibitively expensive. It's so expensive we wouldn't put things there if that particular location didn't have insanely good radio reception compared to what we can achieve down here.

Starlink's only main advantage is military. It gives him control of a global network that can't be easily controlled by sovereign governments. It's one of many reasons he's doubled down on trying to get embedded within the US government. There's not enough money in selling people in remote places internet to pay for this whole thing.

Why say this then? A few reasons. For one, he's hoping to add pressure to get more environmental protections scrapped. Even if politicians don't scrap those, he can use the panic to divert investment money to himself by pretending to have magic beans. And then there's his need to keep up his Tony Stark persona. Partly, he's a deeply insecure dweeb. Partly, his public investments are somewhat meme stocks drawing a lot of retail investment from soy faced tech fans with cushy IT jobs.

They're in low orbit to minimise ping, like anything in low orbit they die after running out of propellant

Things in medium orbits also die when they run out of ability to raise their orbit (notably the ISS, if left alone it would fall to earth in several decades), the low orbits make cleanup of the exhausted satellites happen quickly

All in all it's a good thing