Configurability is great but without good defaults it can also be a liability. Would-be users will bounce off long before they like the software enough to pore through pages of options.
Until about 2022 this was fine, then they introduced things like shifting the scrolling window, breaking mouse support, I think changing search to highlight text etc.
That's fine, but that means everytime I run it on any machine I have to now deploy a vimrc to fix it.
(I think I noticed the regressions starting in vim 8)
Same with no screenshots on github projects (For GUI projects)
Not to mention all the emacs distros that now exist for people who do want a very different configuration. I maintain that default emacs is fine though and if the user wishes to get really in tune with emacs, emacs is one of the most pleasant environments to learn thanks to help pages and how flexible elisp is to evaluate and poke and prod around with and how easy it is to debug.
I think most modern editors will try and introduce mutlithreading and other features that emacs did not do due to it's age and is better for it as it means elisp code just works together and less worry about synchronization and other bits that would exist with more modern ways of approaching the problem (not saying the approach it's self is bad, but for an editor emacs and the decisions around it are largely very good and surprisingly so)