It's simple: banks don't want the people they've fleeced to realise that they no longer have a role in the present age. If you let legal tender be exchanged directly via a central bank (which is semi-public by nature), banks lose a huge amount of liquidity that fuels fractional-reserve banking through loans made to generate massive amounts of cash, and without these, the banks are bust.
In many countries, at least some banks are nationalized. India’s biggest bank SBI (State Bank of India) is a PSU (Public Sector Undertaking).
UPI still connects with bank accounts.
My question was about something else: why EU doesn’t try and develop a homegrown card provider? It would provide exactly what MC/Visa does. Are we beyond that point in terms of technological advancement? Some other reason?