The fact that Musk can fire thousands of staff, and the Twitter site runs just fine as far as I can tell, means it was a highly bloated and inefficient operation.
Sounds like a government bureaucracy, which it effectively was
Not necessarily. As long as everything is running fine, you're golden. Suppose you have a router in your datacenter go wonky though? You wouldn't miss the network guy until you can't access your internal or external networks. There are many other such things. You might not notice anything amiss about your database until some preventative maintenance job that cleans out certain types of records every week or so doesn't get run. Then you start noticing sluggishness and don't know why. Everything is good with your SSL Site certificate until it expires... You have to be smart about exactly what institutional knowledge you lose. Some stuff my well cruise along on remote control... until it doesn't.
I've been doing IT a long time. I've seen a lot of bad things happen when some just assumes because everything was running fine that it would continue to do so.