Does the government view it as 2 throats to choke and so the risk is 'worth it' or is it just a condition of gilded age II and corp and political greed and corruption?
Why did we make all those monopoly laws only to completely forget they exist or why we ever made them?
It's mostly just the way things turned out without government intervention.
American Express' card started in 1958, as a pivot of their then already 100-year-old business: https://en.wikipedia.org/wiki/American_Express#1920s%E2%80%9...
Visa also in 1958 as a Bank of America (and friends) card, which quietly expanded into the mid-60s: https://en.m.wikipedia.org/wiki/Visa_Inc.#History
Mastercard in the mid-60s from banks who BoA wouldn't invite into the Visa clubhouse: https://en.wikipedia.org/wiki/Mastercard#History
And Discover in the mid-80s because Sears was big enough to be its own financial services firm: https://en.m.wikipedia.org/wiki/Discover_Card#History