Yes, its possible to live on BTC only. We you are a sovereign individual that dedicated years to learn the way and you've made it your mission to educate others as well. Most people are not willing to do the work required to use BTC for EVERY situation.

The easiest option is to pay taxes, groceries and utilities in Fiat. It's easier to pay taxes than to avoid them.

Shitcoins offer easy privacy when privacy on BTC is hard. The easiest method for darknet is shitcoin.

The flower does not dream to educate the bee on the utility of pollen, it simply flowers and the bee comes.