I am a bit skeptical.

You only have to look at the ruby ecosystem and the recent mass-expulsion of long-term developers from rubygems/bundler via RubyCentral going full corporate-mode ("we needs us some more moneeeeeys now ... all for the community!!!" - or something). While one COULD find pros in everything, is what is happening in different programming languages really better for both users and developers? I am not quite convinced here.

I am not saying the prior status quo was perfect. What I am saying is ... I am not quite convinced that the proposed benefits are real. In fact, I find managing multiple versions actually annoying. I should say that I already handle that via the GoboLinux way mostly (Name/Version/ going into a central directory; this is also similar what homebrew does, and also to some extent nixos, except that they store it via a unique hash which is less elegant. For instance, on GoboLinux I would then have /Programs/Ruby/3.3.0/ - that's about as simple as can possibly be). I really don't want a tool I don't understand to inject itself here and add more complications to that. My system is already quite simple and I don't really need anything it describes to me as "you need this". I also track and handle dependencies on my own. (This is more work to do initially, but past that point I just do "ue" on the commandline to update to the latest version, where ue is simply an alias to a ruby class called UpdateEntry, which in turn updates an entry in a .yml file, which then is used to populate a SQL database and also downloads and repackages and optionally compiles/installs the given package, e. g. "ue mesa" would just update mesa .tar.xz locally. I usually don't automatically compile it though, so "ue" I just use to update a program version or simply change it; it also accepts an URL of course so users can override this behaviour as they see fit.)