Interesting, brief article that says many people, not necessarily hearing impaired, want closed captions displayed when watching TV, and discusses reasons why:
Why You Can’t Hear TV Dialogue
I definitely want closed captions on all programming (except live broadcasts, where the caption delay is just too confusing) or unless I have a ReSound TV streamer sending the sound straight into my ear. I thought my problem was that newer HDTVs almost never these days have loudspeakers facing the viewer; typically the sound goes down, or reflects off a wall behind. I need direct line-of-fire for good speech comprehension. But apparently the issue may be more general and has to do with the way sound editors mix dialogue these days.