What is not perfectly fine is using GitHub as your package host, CocoaPods/Specs is the equivalent of Debians APT using one big GitHub repo to host all their packages. It has 92567 commits and 6872 contributors.
The big differences seems to be in the way they do their thing: I'm reasonably sure homebrew just git clones then updates the local repository normally[0], it has "only" 2500 files in Library/Formula, and because of its different subject it is way less write-active, CocoaPod has 1k commits/week which look to be increasing pretty much constantly, homebrew is around 350 with ups and downs.
Also not sure it matters, but homebrew has lots of commits updating existing formula, cocoapod changes are almost solely addition (publishing a new version of a package adds a new spec and doesn't touch the old one)
[0] which is exactly the bread and butter of github
Most of the changes committed to Homebrew are formulae-based; of the ~5600 contributors in Homebrew's lifetime only ~430 have contributed to the core code.