SMTP got a toehold before the eternal Corporate Age of the Internet practically ended open protocol development, because it was far more useful on intermittent

SMTP got a toehold before the eternal Corporate Age of the Internet practically ended open protocol development, because it was far more useful on intermittent connections, and on terminals one only used a few minutes a day. Chat didn't get super-useful until everyone had a screen in front of them or on them just about every waking hour. People used it before (I know, I was there, and I did) but it was more of a "see who's on and chat with them" than what it is now.