It is definitely possible to live without banks. There are many already who utilize cash or checks only and buy things in this manner. Living through cryptocurrency is also possible in most areas now, since you can use it to buy off Amazon with https://purse.io/ and obtain many types of services on https://www.bitrefill.com/?hl=en.

There is also OpenBazaar where users can trade eachother directly P2P:
https://openbazaar.org/

At least in the United States, it seems very possible to live without banks, provided that you've set up a system to earn in cash or cryptocurrency, you can always exchange them to get what you need, and I think that it will only continue to become easier.