Both experimented with successful superstores. Now look at their different responses. Kroger concluded that every one of their stores would have to be converted to a superstore or terminated, and that it would take 30 years to do it. So they did just that. Kroger went on to beat the market by 10 to 1 from 1973 to 1998 and ended up as the number one grocery chain in the United States.
Companies think they're going to make themselves better by doing more.
Instead, they look for the stupid things they're doing that are impediments to greatness. Only then do they very selectively add new things. Second, recognize that building greatness isn't significantly harder than perpetuating mediocrity. Granted, building greatness is a lot of work. But they have a lot more fun.