>So a $4b data center on Earth delivers the same value as a $40b data center in Space?

It may do so, initially, compared to a new-build DC.

But, critically, you can upgrade the racks in an already-built DC without demolishing the entire building. You can't do that in orbit, so the full lifecycle ROI is lower.

Orbital DCs are constrained by cooling and by bandwidth. Even a space-to-ground laser (which does not currently exist in a sufficiently-mature form) has a fraction of the bandwidth of a proper terrestrial fiber line. So you're paying at least 10x for essentially a disposable datacenter that can't move as much data in or out, and likely will not be as powerful as a terrestrial DC because of the cooling constraint, just to have it in space because reasons.

I don't see the business case, at all.

This is so transparently another hyperloop-esque pipe dream invented for the sole purpose of inflating SpaceX's valuation.