Bitcoin is not widely used for dally payments yet, so volatile prices makes it difficult to use as a stable currency
This is the main reason why I don't think bitcoin will replace fiat and elimate banks. Even if our fiat currency is decreasing in value over the past years because of inflation, it will still continue to exist together with banks since using bitcoin on a daily basis is still very difficult.
Aside from its volatility, businesses also not want to accept it on their payment system since they avoid conflict with the authorities.
And besides, the government won't just accept any other currency other than their fiat. It is like their identity that can separate from others. Traditional banking will stay as they have purposes that ordinary people need like banking services for mortgage, real-estate loans among others.
For now, I don't see that btc or any other alt will replace the traditional banking that we have. They are still vital in the financial aspect of the government. And we all know that everything is connected with financials when it comes to the economic aspect of any individual, or any entity. So in short, we can't eradicate the traditional banking so fast, it will remain vital in the financial ecosystem.