I believe the answer to your question would be when the big supermarkets accept some form of btc for their goods.
well it could be right , i think bitcoin would never be convenience for transactiom cause the volatile of the price but still there a way like using pundi x project that helping people and merchant to accept transaction using cryptocurrency.
in my opinion if that person can use or make a lot of money from investing. and can meet the family's economic needs. and can shop with bitcoin. and bitcoin is recognized by the state as a valid currency