Most of Silicon Valley is not as highly indebted as Tesla. Apple, for instance, could literally afford to send all of its employees on vacation for 10 years while their headquarters is being rebuilt, without going into debt (Not that they would, of course).

Your typical Internet startup wouldn't lose its means of production, which are people with computers, assuming they are deployed to the cloud. Even those that do any kind of hardware (say scooters) aren't the factories elsewhere and then shipped?

Are many/most companies with billion dollar valuations so exposed?

I would imagine most billion dollar companies have multiple sites and manufacturing and data centers spread across multiple sites.