I disagree with your assertion that Bankers will never allow cryptocurrencies. I work in cyber security and my customers are almost exclusively banks and other financial institutions. Many have or are making crypto currency plans from accepting, to trading to even creating their own.
I work in advanced IT in the financial industry. Yes, various banks are currently looking to implement blockchain technology for their benefit - but none are attempting to turn it into a replacement for currency that is based on treasury securities - like BitCoin has attempted.
International banks and central banks would never allow it.