They Should Think Outside The (Big) Box
Brick & mortar vacuum shops are too worried about competing with the big box stores, trying to sell the flavor of the month, gimmicky, plasti-vacs. They figure their edge is the service angle.
Do they offer any models at all, like the one you're buying the bag for? How are they going to sell the HEPA rated, new-fangled bagless machines, when the vintage design machines can boast the same HEPA filtration? Either they're ignorant of the changes, or hiding them. They should think outside the box, and sell what the department stores can't or won't. Shouldn't be too difficult to sell "old technology" machines that actually perform better!