Historically, Walmart thrived in relatively small town, rural areas. When I was homeless in downtown San Diego, I had to take a bus elsewhere to occasionally visit the Walmart. There aren't any in the downtown area. They don't typically do well in the big city.
You presume people have those options. You presume they can readily and conveniently get to them in a way that makes financial and logistical sense.
In my small town, people who hate Walmart and are happy to drive an hour to a bigger city once a month to "visit the city" and do some of their shopping grudgingly shop at Walmart because it's the only source for a lot of things, even if you are happy to pay more money just to spite Walmart.
People from even smaller towns around us take the bus to shop here (or drive here), mostly at the Walmart. My small town is a regional shopping hub and has shopping and eateries more like a city several times larger because of it. We still can't reasonably get away from shopping at Walmart.
Don't get me wrong. I'm a Walmart fan and wouldn't have moved here if there was no Walmart. I'm just saying I've spoken with a local who hates Walmart and grudgingly does some of their shopping there anyway because they can't always find reasonable alternatives, try though they might.