Well, there is the Microsoft store, but it's clear that moderation is difficult to keep bad or worthless apps out.

Beyond that, there probably isn't a huge demand for a command-line installer or other package manager. Most consumers wouldn't know how to install via the command line, and most enterprise environments will have images with necessary software preinstalled or push them out through SCCM or other such management interface.

All of these attempts at alternate installers really only seem to appeal to developers, but in the scheme of things, there are other more pressing concerns even for them.