I think one thing that scared him away was the word "relevant"... VIM might have as well (very primitive). Emacs tries to do some things that are worth doing, but it brings the user into "textland," not "systemland."
More "textland" than anything else, though that has to do with the medium we're using to communicate "across space and time." What Alan has advocated is that the medium we're using in this particular instance should be a version of "systemland."
It's difficult at this point to come up with an example, since we don't have it yet (that I know of), but to give you an idea, take a look at Lively Kernel https://www.lively-kernel.org/