Emacs is built on Unix like vi and everything else. The fact that vi has a less elegant language doesn't affect me, because I don't see much value in adding extensions to the editor. What I need is a sane user interface, which vim provides.
The original Emacs was written for Multics at a time when people outside of Bell Labs were largely unaware of the existence of Unix[1]. It also doesn't follow the Unix philosophy of making small CLI utilities composed with pipes. As I understand it (though I haven't used it), Acme is extended with external programs which communicate through pipes just like the traditional Unix utilities.