DX-7's probably outsold every arranger made in the last ten years by every manufacturer (at least the TOTL and MOTL ones). It still remains to this day the single highest selling keyboard in history.

OF COURSE a salesman is going to know more about his most popular product than his LEAST...

Trust me on this one.. if Tyros 2's sold in the same kind of numbers than the products they DO know about, they would be knowledgeable about THEM and keep them in stock. But a handful of retirees is a drop in the ocean compared to the hordes that buy Motif's and Fantom's.

What would YOU spend your time boning up on, if you were a salesman (assuming you don't have enough time to bone up on everything, which is usually the case!)?

Try MI retail as a living before you get too worked up about the lack of knowledge in most music stores... Either educate yourself exhaustively before you attempt any shopping, or simply be HAPPY to pay a premium for knowledgeable staff and well stocked stores.

You can't have it BOTH ways!