I used to work with Steve. He’s a good story teller. But a story teller tells good stories by having a fairly casual relationship with facts and the truth.
For example, emacs lisp suffers from bitrot. Some core things haven’t changed in forever but also you can’t pick up elisp config from 15 years ago and it’s fine today.
All live systems evolve and change. In this case emacs is just so slow that Steve thinks that it doesn’t.