When you have a big tech company with thousands of employees, the pareto principle comes into play in a huge way: proably only 10% of these people are actually doing any work that directly impacts the platform.
At least half the employees are probably not doing anything really useful. This applies even to tech companies with a mere 100 total employees. At 3000 employees it's probably even more so. Specially with the majority "working from home".
There are probably only about 10 key engineers who understand at a deep level how things are working.
On the other hand, Musk is bootstrapping a hardcode engineering culture where a lot of the platform can be implemented from scratch in a few weeks by top engineers if he can hire them, and I'm pretty sure he can.
His "Fork in the road" email is actually brilliant, many just don't realize it. He is good at making engineers a "high status class"; see this analysis by Samo Burja: https://samoburja.com/how-elon-musk-is-making-engineers-cool...
There are many top teir engineers who are eager to work for him.