No need to replace the millions of packages in npm. I predict there will never be a shortage of new javascript frameworks... No, npm is not THAT package manage

No need to replace the millions of packages in npm. I predict there will never be a shortage of new javascript frameworks... No, npm is not THAT package manager. What I am talking about is a way for a user's Browser to download for example a Python 3.7.1 runtime (and similar packages) once, and use it on different sites and applications. In the simplest form Google or Python.org could serve these files on a CDN. In a more complicated form you could run an application on a range of Python versions, and only download updates when you want and need them.