You aren't getting my point. The small set is not the number of hardware Apple provides. The small set is the number of products Apple provides through the web - basically, the Apple website, the Apple store, the iTunes store, Apple's cloud services and that's about it. Google, on the other hand, has the Play Store, Google cloud services (which are much more complete and broad than Apple's), Gmail, Google Plus, and the responsibility of having to handle 70-80% of the world's searches.
The point also isn't that the same servers handle everything. The point is Apple has greater flexibility to devote more servers (or more server capacity) to iOS updates - updates for an OS and devices they insist on absolute control over - than Google for Android updates. By the way, honest question: does everyone on iOS receive an update on the exact same moment (or at least begin receiving it on the exact same moment)? If not, Apple too "rolls it out" following some sort of sequence.