Hi Tom,
same thing here in Australia. We get 2 types of stores. The "PRO" shops that sell guitars , synths , music software, audio equipment and the really low end keyboards, then you have the other type that sells digital piano's and mostly low end keyboards.
I've pretty much bought most of my keyboards sight unseen, had to go off literature, specs etc. The only store that had a full range of models, was my Technics dealer. Unfortunately he's now gone. He at least knew the basics on how they worked, great player, but when it came to the trickier questions, even he floundered.

Tend to think maybe because there's so many manufactures, and each keyboard works differently, the sales staff just don't have the time to learn all the functions, so it's pretty much a case of you want it, you get it, and then work it out for yourself.

best wishes
Rikki