Mom & Pop shops can really only compete in terms of superior knowledge and customer service nowadays. Sadly, most people prefer the cheaper products above all.
Capitalism, in its current incarnation, is broken.
So you are saying that people prefer cheaper products over superior knowledge and that big box stores are doing well by providing the former instead of the latter... seems like customers are getting what they want and capitalism is working fine. Just because you don't agree that people should prefer cheaper products doesn't mean that capitalism is broken.