In the end, it's going to be Walmart or Amazon. Walmart will at least hire local people to staff the stores, and local stores might be able to survive as ultra-niche places that will carry all the oddball "long tail" stuff Walmart won't bother with. But if you don't let the population have a nearby store that has good prices, good customer service, and a good selection of the things the bulk of the population wants, they'll go online for it, they'll discover that Amazon actually does have everything (well, except for a Chromecast or a Nest), and the nearest fulfillment center will be too far away to hire anybody local (I say "will" rather than "may", because if they're keeping out Walmart, they'll keep out Amazon fulfillment centers too).
And let's not just talk about the selection and the prices. Let's talk about customer service. Big companies prioritize the bottom line, so the last thing they want to do is turn away customers or risk a black eye on social media that can spur a boycott. Small businesses tend to take an attitude of "I'll run my business my way, even if it hurts the bottom line!". Case in point: Macy's has fired multiple employees for telling trans women that they're not allowed to use the ladies' fitting rooms. They have a corporate policy of non-discrimination, and employees who break that policy get canned. Why? Because turning away customers is bad for business, and the last thing they want is for "boycott Macy's for transphobia" to trend on Twitter. A small businesses may very well take the attitude of "I'm not treating you freaks like women, so get out!", they're willing to lose the business for the sake of their principles, and they're not going to face much backlash in a conservative small town. Or you see all the cake bakers who refuse to bake for LGBT people; you won't see that kind of discrimination at Kroger. I am 100% fine with these small businesses going away. They actively make life worse for marginalized people like the LGBT community (I'm a lesbian trans woman myself), so I'll do whatever it takes to accelerate that process and replace them with bigcorps.
And let's not just talk about how small businesses are worse for the customer. Let's talk about how they treat their own employees. Laws requiring employers to provide insurance benefits to their employees don't kick in unless the employer is over a certain size. And it's precisely because of small businesses that the US doesn't have as many employee-friendly laws: it's the small businesses, not the big corporations, who are terrified of the government mandating that employers provide large amounts of vacation time or comprehensive health coverage. Big businesses are big enough to soak the cost; mom-and-pops aren't. And it's not just about benefits: think also what HR departments can do for you. If you work at Walmart, and your supervisor is sexually harassing you, you can file a complaint with HR. If you work at a local shop... your supervisor is probably the owner, so your choice is to either live with sexual harassment or find yourself unemployed. And there's evidence showing that the gender wage gap among pharmacists almost completely went away when pharmacies shifted away from mom-and-pops and towards big box stores that hire people to work shifts.
Whenever I hear stories like this, I think of a handful of strips from Something Positive back in 2004:
Small businesses are strictly worse than megacorps, and they're finally getting what's coming to them.
As an employee, your employer’s HR department exists for the sole purpose of maximizing the net value that the employer can extract from you, the “human resource” being exploited by the company (and if that maximum turns negative, that can be rephrased as minimizing the net harm you can do to the company.)
If they happen to do something that actually benefits you, that's a side effect, not the main goal.
This is preposterous. A small business relies on all the good customer relationships and feedback it can possibly get, running it in a customer-hostile manner is a great way to go out of business. A social media cascade might cost a megacorp some lost profits; for a small business it could easily be your downfall.
>think also what HR departments can do for you
HR departments do NOT work for you; they work for the company. HR is not and will never be your friend. Megacorps don't magically make workplaces less toxic just because they have an HR department.