A legitimate mom-and-pop is never going to compete with larger retailers for commodity items like PC components. They don't have the buying power, they don't have the economies of scale and they can't offer meaningfully better support or curation. The "mom-and-pop" retailers who can compete are generally doing something shady, from grey imports to outright counterfeiting.

That's far from the case in all verticals. I have bought tons of stuff from small specialised online retailers, because they can meaningfully compete in niche markets. If I want a woodworking tool, my first port of call is Workshop Heaven, because they sell a carefully curated selection of extremely high-quality products. Everything they ship has been QCed by someone who actually knows about tools, so I'll happily pay a premium in the knowledge that I'll never get a dud. I'll buy a tool from a brand that I've never heard of, because I trust their curation. I look forward to seeing their newsletter in my inbox, because it usually highlights cool new tools that I haven't heard of.

IMO, the future of mom-and-pop retailing doesn't look like mom-and-pop retail - it looks like a boutique. A small selection of carefully curated products, a fanatical commitment to quality and genuinely useful pre- and post-sales support. To survive in a post-Amazon world, small retailers need to evolve into niche brands in their own right.