Lyft seems like the kind of company that would be more successful run extremely lean than trying to focus on growth. There simply isn’t that many major metro areas after all.
I'm starting to think that many companies seem to define "growth" in terms of headcount, rather than revenue or marketshare, and that they overhire based on a perception of needing to grow the company whether they need the people or not.
Lyft is a mature product. Heck, they felt like a mature product when I used them for the first time five years ago.
So why would they need to keep hiring engineers? What new features necessitated the hiring of additional teams?