I wonder sometimes if the almost-military model of business hierarchies is intentional, unintentional, or emergent behavior of the system.

The line manager and lead developers are not unlike non-commissioned officers. They are supposed to be able to talk to the grunts, and even though they don't do the "shit", getting shit done is not abstract for them. They know how to do it in a more concrete way. If they didn't, nobody below them would respect them. (Though I have heard tales of new NCOs being sweated by their reports because they clearly did not know anything in a concrete way. They were either going to learn or they were going to be forced out.)

For everyone else there's a lot of up-or-out. If you've been a middle manager for 20 years there must be something wrong with you.