Visa and MasterCard get a lot of hate as they are definitely a duopoly. But imagine they never existed and PayPal or some other Fintech was the non-cash payment monopoly.
Far less things you'd be permitted to purchase, far more random account closures for violating intentionally nonspecific TOS. Worse customer support than we have now and even less consumer protections.
MasterCard and Visa hearken back to a time when KYC was far less aggressive.