How do you plan on doing that if most stores and banks stop accepting cash, and to get a debit or credit card you need to show government ID, which is electronically verified (it has an RSA keypair, signed by the government, stored on its chip).
Most stores don't stop accepting cash right now, and I doubt they will in the future. I know more shops refusing credit cards than ones refusing cash in France.
You can also live without a bank. Several people I know do so. Again it's work, but it's possible.
A lot of the time, people saying it's impossible really are asking "how can I keep my confortable life 'as-is' while going off the grid". THAT is impossible. You can't live your current life, because it depends heavily on the system.
How do you plan on doing that if most stores and banks stop accepting cash, and to get a debit or credit card you need to show government ID, which is electronically verified (it has an RSA keypair, signed by the government, stored on its chip).
It becomes impossible.