I discovered a tool called junest (
https://github.com/fsquillace/junest) that appears to work for installing Emacs without root access.
Given that many users do not have root access, it is crucial to provide an official, well-documented method for installing Emacs in such environments. Addressing this issue should take precedence over introducing new features, as it will significantly improve the user experience and make Emacs more accessible to a wider audience.
In the current state, recommending Emacs to new users can be difficult, as the installation process requires a considerable amount of Linux knowledge. By streamlining the installation process for non-root users, Emacs will become more user-friendly and attractive to newcomers.
As for what this officially endorsed (and tested) way of installing emacs without root should be, I don't have the expertise. But perhaps GNU Guix could officially support a non-root mode, as it seems technically possible. Alternatively, the Emacs installation documentation could include instructions on using a non-root package manager like junest, which should be tested to ensure compatibility with Emacs.
> We have neither the manpower nor the motivation to maintain build
scripts that automatically adapt to every oddball system that arrests
the fancy of Emacs users, or to write instructions for such systems
ourselves.
I don't think a non-root Ubuntu system is a rare occurrence, and in general, a non-root Linux should be quite common, especially in universities, where new users often are.