Genuine answer: Setting up Facebook WOULD be extremely challenging for a company like SpaceX. There's a reason Facebook is worth about 10x what SpaceX is worth, and most of that value doesn't come from the ability to build software. Facebook isn't even particularly good at building software.
To give an example in a closer domain: Look at how long Google lost money on cloud services through 2022 (over $15B in loses), and now only makes money by creative accounting (bundling "cloud services" together versus breaking out GCP; Microsoft does something similar with Office 365 and Azure).
Like many potential customers, I would not consider GCP because:
1) Google "support" is a buggy, automated algorithm which randomly thwacks customers on the head
2) Google randomly discontinues products
3) I've seen a half-dozen to a dozen instances where buying from Google was penny-wise and pound-foolish, and so have many other engineers I've worked with.
Google's overall attitude is that I'm a statistic defined by my value to Google. Google can and will externalize costs onto me. That attitude is 100% right for adwords and search, which are defined by margins, but not for something like GCP. If I am going with a cloud service/platform, I'll go with Amazon, Microsoft, or just about anyone else, for that matter.
That's not that Google is a bad company. Google actually did have the skill set to build the software and data centers for a very, very good cloud provider. It's just that Google's core competencies lie very far from providing reliable service to customers, customer support, or all the things which go into providing me with stability and business continuity.
"Fixing" this would require a wholesale culture, value, and attitude change, and developing a core competency very far from what Google is good at.
I put "fixing" in quotes since if you develop too many core competencies, you usually stop being good at any of them. Focus is important, and there's a reason many businesses spin out units outside of their domains of focus. If Google is able to become good at this, but in the process loses their edge in their current core competencies, that's probably a bad deal.
FWIW: I haven't yet formed an opinion on NVidia's cloud strategy. However, their core competencies appear to be very much in the "hard" domains like silicon, digital design, machine learning rather than "soft" ones. Another relevant example for what can happen when hard skills are de-emphasized at engineering-driven companies is Boeing (if you've been following recent stories; if not, watch a documentary).