Who in his right mind would use an editor that cannot even do symbolic integration? Joking aside, I suspect that this is mostly due to two factors: 1. Emacs w

Who in his right mind would use an editor that cannot even do symbolic integration? Joking aside, I suspect that this is mostly due to two factors: 1. Emacs was used by a lot of smart people, and one of them, David Gillespie got carried away a bit. 2. Thirty years ago, when David Gillespie first started working on calc, emacs lisp (despite at the time lacking even floating points numbers IIRC!), was probably one of the most expressive fairly widely deployed languages around, particularly for the type of symbolic manipulation you need to do for computer algebra. And unlike other things that were used by smart people 30 years ago, emacs still sticks around, so survivorship bias also plays a role.