Re: Make it hard for their customers, the customers will avoid the stores.
Unfortunately with both Guitar Center and Sam Ash, they don't stock very much of anything. I say unfortunately, because it would actually be very easy to do so. Anytime I see open wall space behind the counter, and often there's a lot of it, I know there are parts and other items that aren't carried there. Seriously, good luck getting a whole set of rods for that used snare you just bought... or wires you like... or a butt plate. Good luck also putting together a set of cymbals. GC carries so few Zildjian items (for example) that you'd be lucky to find more than one ride cymbal in a given size. Yet, the cymbal walls have a lot of space to add more cymbals.
Granted, lately, finances have kept some stores from being well-stocked, but GC and SA have always been weak on selection. The salespeople's jobs there have been equally difficult as result, and of course they try to sell what's on hand. If there was a better selection, their job and the customer experience would both be smoother.
With all due respect to local stores with good drum departments, dedicated drum shops are almost always going to have the best selection and service. And because the shops are usually manned by the owner and sometimes their family as employees, the knowledge and dedication to service will also be better, not to mention that they'll be there month after month, year after year, and good relationships with people behind the counter really pay off.
And thanks to online competition, the small shops began offering really great prices (which they weren't always doing until recently,) so the idea that their prices are high is old school.