That is true.
The answer was; don’t use the proprietary marquee it’s an abomination and always was and hence why it never made the normative technical recommendations in the first place.
That or politics. We see <embed> has been allowed to crawl back into the specs. 
Well, embed did have some merit at one time (even though proprietary and non standard) due to M$ failing to support OBJECT correctly. Albeit now it is pretty much a case of the HTML5 fanboys documenting it and strangely deciding; AUDIO, VIDEO and OBJECT aren’t enough. LOL
could just be, the spec must be BIGGER!
sorry had to post that cause I just discovered Brunel was like the most awesome civil engineer evar.
Scrolling text doesn’t need to exist. Even if <marquee> WERE a real tag, I wouldn’t use it.
A javascript solution with play/pause/rewind buttons would work, but at that point you should just wonder if something like that actually adds to the user experience something that a plain old box with text can’t achieve.