Very good post BJL.
I think many professional photographers forget that most people who are going to be buying cameras are NOT professional photographers. Most people are not going to want to spend $4,000-$8,000 on a camera back and $1,000-$2,000 on a lens. Most people are going to want to spend $800-$1,500 on a back and $250-$800 on a lens.
Your same reasoning applies to the Canon EF-S lenses. I have heard people moan about these because they won't work on a FF back. Well, that's good, they're not designed to. They're designed to give reasonable quality for users of crop lenses.
Your statement, "My thanks to Nikon for making it a bit clearer that the introduction of FX is not a move away from DX, but just an expansion of our options," is a bullseye ...
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