It sort of reminds me of The Collapse of Complex Societies by Joseph Tainter. These companies are their own microcosms of a complex society and I bet we will see mass layoffs in the future, not from AI but from those companies collapsing into a more sustainable state.
The reality is that you could run LinkedIn with far, far fewer people. You probably need fewer than 100 for core engineering, and likely less than 1,000 overall if you include compliance, sales, and so on - especially since a lot of overseas compliance stuff is outsourced to consulting firms, it's not like you have a team of lawyers in every country in the world.
Before there was so much money in the system, we used to run companies that way. Two decades ago, I worked for a company that had tens of millions of users, maintained its own complex nationwide infra (no AWS back then), and had 400 full-time employees. That made coordination problems a lot easier too. We didn't need ten layers of people and project management because there just wasn't that many of us.
Keeping a website running with high uptime is not the goal. Maximizing revenue and profit is. The extra people aren't waste, they're what drive the incremental imperceptible changes that make these companies profitable.
Did reducing waste affect the user experience or uptime of Twitter? Not really.
But advertising revenues plummeted, because those extra employees were mostly not about the user experience or keeping the website up, they were about servicing the advertisers that brought the company revenue.
Maybe there's a correlation there?
I'm implying that big companies couldn't make as much money as they do without all the employees they have.