This is indeed correct. Wikimedia overall uses less than 2000 bare-metal servers, so yes the infrastructure is tiny compared to those.

What can be interesting, I think, is that you have a completely open infrastructure that has to solve problems on a global traffic scale.

If people are interested in knowing more, I suggest you also take a peek at the wikimedia techblog, specifically to the SRE category https://techblog.wikimedia.org/category/site-reliability-eng... and the performance one https://techblog.wikimedia.org/category/performance/