I don't believe the standardisation point is true. The banks came together to create the EMV (Eurocard - Mastercard - Visa) standards, which define eg how chip & pin works. The mobile industry is also very big on standards.
The issue is about who owns the customer. There's the one secure element (the SIM/bank card chip) - who should own that? Technically both operator and bank can coexist on the same card, but the commercial position is not so simple.