Will full Bitcoin adoption require that retailers transact almost exclusively Bitcoin? Similar to small shops in our local communities that only deal in cash and not debit or credit.
The retailer doesn't have to accept fiat when there are so many easy ways for buyers to exchange their fiat into Bitcoin.
Businesses have to accept legal tender in most countries by law. That basically means unless the government changes this law (not going to happen) you'll never have BTC as the only form of payment method. I'd personally be more than happy if we could just get it to the same level of acceptance as PP and CCs. That would by all means be more than enough to keep Bitcoin going for a long time to come.