If hi-fi ever grows into the mainstream...
I doubt that will ever happen. It takes a lot more work and attention to the details to be worth the time to a majority of people.
So (too?) many gadgets currently available to amuse the masses instead.
That's why I so loved growing up in the 70's, so many people into audio. Big ass speakers, reel to reels, super expensive Nakamichi worship... etc.
I still hold out hope that music in high res surround sound will capture the imagination of the young. All we need is a young artist/band to create the next "Sgt. Pepper" or "Dark Side Of The Moon" in that format exclusively. Oh, and for it to be popular.
Super Furry Animals tried at least with "Rings Around The World"...