It's about creating a flywheel for scale.

Getting better at creating and erecting solar panels & AI datacenters on earth is all well and good, but it doesn't advance SpaceX or humanity very much. At lot of the bottlenecks there are around moving physical mass and paperwork.

Whereas combining SpaceX & xAI together means the margins for AI are used to force the economies of scale which drives the manufacturing efficiencies needed to drive down launch etc.

Which opens up new markets like Mars etc.

It is also pushing their competitive advantage. It leaves a massive moat which makes it very hard for competitors. If xAI ends up with a lower cost of capital (big if - like Amazon this might take 20 years horizon to realize) but it would give them a massive moat to be vertically integrated. OpenAI and others would be priced out.

If xAI wants to double AI capacity then it's a purely an automation of manufacturing problem which plays to Elons strengths (Tesla & automation). For anyone on earth doubling capacity means working with electricity restrictions, licensing, bureaucracy, etc. For example all turbines needed for electricity plants are sold years in advance. You can't get a new thermal plant built & online within 5 years even if you had infinite money as turbines are highly complex and just not available.

Hmm, Elon really did run that flywheel pretty well. He built the Roadster to drum up some cash and excitement so he could develop the Model S, then he used that success to do the Model X, and then he expanded capacity to develop the 3 and Y, and he reinvested the profits to develop the Model 2, finally bringing EVs to the masses, displacing ICEs everywhere, and becoming the undisputed leader of both EV and battery manufacturering.

Oh wait, that didn’t actually happen, because he got distracted or something? He doesn’t really have battery capacity worth writing home about, the Chinese are surpassing Tesla in EV manufacturing, and Waymo is far ahead in self-driving.

The amazing space computation cost reduction process sounds rather more challenging than the Model 2, and I’m not sure why anyone should bet on Elon pulling it off.