Why do a `git clone pkg && cd pkg && ./configure && make && make install` instead of just a `brew install`? The whole point of a package manager is to make installations and upgrades easier.

Homebrew never was a package manager until recently. It was in the name, it was designed for building packages from source on your local machine.

Now your are just quibbling over what ultimately is a minor difference.

"just"

Also need to track down and install all of the dependencies, and the dependencies dependencies and all the way down, and figure out the right configure flags to pass, and what environment variables it needs and where it expects to look for header files and the like.

Doing all of that from scratch takes hours and hours. Homebrew lets me not worry about that, and instead be productive.

It also takes care of updates