For better or worse, when you get to a certain size you absolutely NEED that level of bureaucracy. You can't get 120,000 full time employees plus probably another 100,000 contractors to work together without establishing a clear hierarchy that everyone inside it understands. A smaller company can have different approaches because they will have a dense network of employee relationships, and can work together off of those relationships. However, at six figure employee scale by necessity you will end up with a very very sparse matrix of employee relationships, so you have to have something else to get results.

A lot of really big companies have super flat hierarchies when I worked at one we had MPG2, MPG4 then Senior Management U,T,S

Promotion was brutal you might have 20 MPG4 slots every 18 Months for the entire Division (60k FTE) - just getting to the Board Stage was tough enough.

I think a MPG2 was equivalent to a Captain an S was a Grade 7 (GS15 in US terms I think) Full Colonel

You just proved the GP's point. Whether the hierarchy is flat or not is irrelevant, they still have the bureaucracy around leveling and authority/responsibility.