> A lot of these radically flat orgs expect ICs as "senior engineers" or "staff engineers" or some other made up title to do some ad-hoc mix of IC, people management, project management, etc.

Then they fire someone randomly and wonder why the company fell apart because that random was doing the bulk of the unappreciated 'glue' work but because their manager never recognized them for that work or bothered to promote them, no one knew besides their co-workers