Pretty much this. Places like Parts-express have been creeping more upmarket with their own brands like Dayton Audio to fill some of the gap, but they are still

Pretty much this. Places like Parts-express have been creeping more upmarket with their own brands like Dayton Audio to fill some of the gap, but they are still more downmarket hobbyist niche and probably won't ever be in mass market stores. The same thing that happened to cameras being replaced by good enough phones happened to stereos, just with soundbar/box type appliances.