I meet the same problem in supermarkets (where can I find ...) and most hardware stores (do you have something to fix...). The main exceptions are with older people who take the trouble to find stuff out. If I ask most of the shelf-fillers they have no idea.
I do know of a friend whose teenage son (many years ago) worked on Saturdays in a computer store and knew about the products and so would advise customers about what they needed. He was told off by the manager, as he was just supposed to be selling stuff.