Kroger owns 28 businesses, most of which are grocery stores, like Dillons, Harris Teeter, Fred Meyer, etc. Looks like Albertsons owns about the same amount of other grocery stores. It all conglomerates now. Practically monopolies, but not quite. There’s at least one other huge grocery conglomerate, but I don’t know who it is.
Kroger is the third-largest private employer in the United States (443,000 employees).
https://en.wikipedia.org/wiki/Kroger
The Randall's near me that is closing was an Albertson's store. It has always sucked and we've always driven a few miles out of our way to go someplace better. The Randall's "Flagship" stores are usually pretty nice. Ours was not a flagship (we called it a Randall's Garbage Scow). Its spot is being replaced with a store called El Rancho, which has previously been in Dallas and is new to Houston.
IMO, the best grocery stores in Houston are the HEB stores. I drive a few miles to get to one. We also have an Aldi in our neighborhood, but they don't carry much variety.