I like your optimism and I honestly hope you're right.
That being said, I would suggest that the core competencies involved in getting into hi-fi vs. building a dock are at different ends of the spectrum. So I don't know if the comparison is (and I hate to use the expression) "apples to apples".
As far as diversifying the "Made for iPhone" market, it seems like Apple's dock didn't stop third party manufacturers from getting into the game. By creating a basic, no bells and whistles dock, Apple, in my opinion, left the door wide open for anyone and everyone to improve on the design.
The fact that Apple has chosen to develop a solution for their retail stores out of necessity says something to me. Even if Phil Schiller doesn't believe Apple needs to make a dock, the retail division needs them. And I can't imagine Apple ever using a third-party dock across their stores (when one that meets their design standards comes out) to show off their flagship product.
Bottom line: You're optimistic and I'm wondering if this is another sign of company struggling to do what they seemed to do for so long, figure out what people wanted and needed and gave it to them before people even knew it.
imo