Look at job ads. Many, many companies of all sizes ask for experience working with massively distributed architectures, "over 1,000 servers" and things like that.
FWIW I built and worked on a server farm of upwards of 2,000 physical servers with myself and one other. (with minor labour support from another team of 3 people when needed).
it's possible to work in a small team and be effective even at large scale.
it's possible to work in a small team and be effective even at large scale.