Say what you will about Homebrew, but we need more package managers that can easily install without root. Not everyone has the time and energy to compile from source, and often it's a circular problem - I need to compile and install Python 3.7, which needs openssl, which needs to be compiled from source, which has even more dependencies... ad nauseam.
Why do we need more of them when we already have a number that are capable of deploying into a home directory? As someone who has worked on software that has needed packaging, and someone who tries to help out with packaging for a distribution, I can't imagine why we need more for the sake of having more.
Per my original comment, nix can do this, for example and already has an enormous number of packages packed, pre-built/cached, ready to go.
