The problem is that even bitcoin users believe more in fiat than btc.
Seriously, I don't believe in fiat at all. I just use it because it's a necessity in my daily life. No way I will believe in something that is only going down in value, and thus forcing people to put their money to work in order to not fall behind. That's why I have a good portion of my total wealth in Bitcoin. It's not only to avoid seeing my wealth lose value, but also to escape from the banking and governmental system. It's a complete package that Bitcoin offers me.
If they thought btc was the bomb, you will see more customers requesting that street stores add bitcoin payment options.
The main issue here is that people see Bitcoin far more as an investment tool than a currency tool that people can use to purchase stuff. Also take in mind that in most of the countries it's simply more convenient to just keep using fiat in order to buy your daily needs. Add that there are also zero fees involved when you purchase stuff, plus you don't have to worry about the volatility. Why would people then bother to use Bitcoin as local currency?