It’s not just “small towns”.
It’s really anywhere that is not a major metropolitan city.
For example, in the Phoenix MSA (or metropolitan statistical area), outside of cities like Phoenix and Scottsdale, basically every other city in the Phoenix MSA is littered with strip malls overstuffed with chains and big box retailers.
Same is true with the Sacramento MSA.
This is largely driven by risk-averse landlords.
Or lack of financial means to cover the rent. That’s why so many (strip) malls remain empty, or get a chain in bc they have the company cash backing it.
My uncle lives in Colorado Springs, initially in the new build area with chains, now closer to the old part of town which has a few more independent and slower food options, but there’s still a Burger King with a mile of his house.
There are plenty of indie spots if you seek them out, but 90 percent of the population are happier with the chains. 
I push for indie spots when I visit, but all my exposure to Cheesecake Factory and Macaroni Grill was through visits with his family. He likes spicy food so he was always game for indie Thai, Mexican or Indian when it was the 2 of us, but his wife and youngest daughter are 2 of the plainest eaters in North America so we always had to work around them.
In the burbs of the Greater Toronto Area and midsized Ontario cities like London, as well as in Calgary and Edmonton, this polarization is happening, where there are a lot of new indie or small chain Indian Hakka, Turkish, Indian Street Food, ther halal stuff and Shawarma shops are opening at the same time that Chick Fil A , Jersey Mike’s and Jimmy John’s are moving into town. The relatively cheap fast food or fast casual food options are becoming more interesting and more white bread at the same time.
That’s like some of my co-workers, who think kiwis are exotic and teriyaki chicken is hardcore Japanes.
We would go to an indie pizzeria, the youngest would refuse to eat any of the pizzas ordered, then she would eat microwaved frozen pepperoni pizza at home.
I just tried a Jersey Mike’s sub for the first time. It was a cut above (no pun intended- they slice the meat to order) Subway. As a matter of fact, apparently Subway is doing that now, too. Subway rolls are awful, though. I like non-chain subs.
