It more than just the lack of knowledge of store employees that cost CC. Its having to compete with the internet, ID only companies and traditional B&M brands going toward ID.
Just look at what is probably the largest CE brand, Harman International. Harman has its own internet factory store, its ebay store, that sells Infinity, JBL, Harman/Kardon speakers, receivers, amps etc.
At the same time, the only JBL series BB sold was the lowest priced, bottom of the barrel lines and if you wanted the better, more expensive series you had to look elsewhere. Infinty was never sold there, as best as I can remember.
Just no way BB or CC can compete with the internet pricing. And although you won't get any real customer service via the internet, pretty much didn't get any at BB or CC, from the ones I ever went into, much less anyone who knew what they were talking about.
Of coarse, if you want the other higher end HI brands, you still have to go to a quality B&M store, or Synthesis dealers, be they far and few between.
And although we all love the net, that's what has killed the B&M retail as far as CE.