Large co's play different games than mom & pop. They can afford some near-term losses if they can make the case it prevents competitors from gaining a foothold. Banks can justify rent on a seemingly empty branch in an expensive retail area if it supports catchment area of desirable clients that visit in person once every 18 months. Etc.

Scale in distribution, especially marketing / brand / name recognition

I think people just like chain stores better. Plus they can take advantage of bulk buying for materials, services, advertising, etc.