Ive worked at 3 places, sizes: <10, ~10k, and ~20k.
I cant even imagine 100k. 100k for Toyota or Walmart, sure, that makes sense. But at tens of thousands of engineers you must have a lot of people not doing anything. Even at 20k, so maybe 5k engineers you only have so many people pushing on new stuff. Most are doing maintenance on crud and batch apps and keeping up with whatever "initiatives" are being pushed while attending meetings.
Most impressive to me imo are the instagram type companies that have 20 employees when they are sold/ipo or whatever.