However, users have to first know it's an option to use. Why not add it by default, and even have a menu option to install package? VSCode will even recommend popular packages depending on file types you load.
Because it's not core emacs. Core emacs uses ELPA, which has fewer packages.
Don’t you see why that’s a problem? Multiple package managers, with none enabled out of the box, and poor usability?
It's not multiple packages managers, but different sources for packages.