To directly answer your question, people from other teams were available if for some reason I was not.
Facebook is doing 1 engineer to 20K servers: http://www.datacenterknowledge.com/archives/2013/11/20/faceb...
The number of companies who can do that are single digits, but 1 person per ~5000 servers is absolutely reasonable.
I would also be suspicious of 1:10,000+ numbers as they often don't include people that are part of the server team but not standing in the data center. Aka Facebooks 3 person dev team, a manager, whoever designs there HW, the team spun up to do mass HW installations etc.
In the end AWS covers a lot of seperate costs which are only really obvious as you keep scaling up.
I'd like to see a similar analysis for say 50-100 servers, and see if AWS really costs more vs. colocation when you add in the resources to setup and maintain the infrastructure.
PS: I could see a team of 10 people handling 55,000 servers though. But that's serious scale and fairly lean.