Big is not always bad, but big also comes with unintended consequences.
We are here to craft beer, not to make cheap beer. If cheap is your goal, go buy BMC and save lots of time money and hassle. Handmade artisanal beer is an art and a science that emphasizes quality and creativity. Large chain retailers aren't there for quality, they are there to drive down prices and command market share. That sounds like the natural bedfellow of mass market beer to me, not obsessive zymergysts in their garages making beers half the world wouldn't drink because it's too dark or weird or not promoted by a pet wearing an aloha shirt and his bevy of large breasted, bikini-clad sudswhores.
Not everyone in this hobby is here to make masterpieces, but the vast majority of us are here because we see and taste a difference between cream of three crops and PBR.
If big box and mega retail start driving the profitability out of beer ingredients and thereby destroy LHBSs we nerds in sheds loose. Most home brew shops are started by people like you and me that love the hobby and want to share that love.
Wally world will not ever carry smoked malt or liquid yeast or have people on staff that know anything about what they sell who love what they do. But they could destroy the hard working enthusiasts' business if we allow them to dazzle us with the smoke and mirrors of low prices. It wouldn't take much to kill those LHBSs off.
So be as cavalier as you want about how your local sucks, but remember that you could be helping kill off MY awesome LHBS, and you are making sure that the terrific guy or gal that might want to start up a new store near you that will rock never gets that chance.