So 3/4 of the main points here are in regards to hiring the right people...
Almost makes me wonder if hr teams/operations shouldn't be measured on just headcount but rather getting the right people in
Once you get large enough your ability to really selectively recruit gets a lot harder when natural attrition means you need to replace X amount of people just to continue operating as before.
Of course earlier on, the fewer the people the larger the impact each one will have so just like the article says about transitioning to enterprise, the focus and requirements of the HR team change as well.