I was curious if this was true so I looked it up. AmEx + Discover have 20% - 25% market share depending on the metric you care about. Bing + DDG have 8%
"Visa holds a 60% share of the credit and debit card market, followed by Mastercard with 30%, according to Ellis, with American Express far behind at 8.5%."
Except in practice, the vast majority of Amex users also have Visa/Mastercard just in case (e.g. Visa/Mastercard users are close to a superset of Amex users).
Also it’s like bringing up search alone when talking about web.
In reality an intermediary called “payment processor” handle all CC brands in single system and they are the ones enforcing ideological punishments to merchants.
Like there’s web search and web browser, card networks and payment processors both should be brought up.
> In reality an intermediary called “payment processor” handle all CC brands in single system and they are the ones enforcing ideological punishments to merchants.
Yes, payment processors enforce the rules, but don't typically make the rules.
As I am sure you can imagine, this can result in plausible-deniability-type finger pointing ("we don't make the rules" / "we're not responsible for the rules being misapplied") when an organization is cut off.
