Nope. I very doubt government will want to relinquish control...
As a sub currency it could gain mainstream use but i think there will be much blood before BTC replace the Dollar.
Yes, me too! I don't think this possible because I still see majority of the public are using fiat and I see no way they are going dump fiat for bitcoin.
Bitcoin also has some issue right now which is "transaction fee" - Bitcoin transaction fee is high, let's say you want to buy grocery or biscuit of kids. just for that you would pay anywhere between $1 - $2 for transaction fee. I see no way people will adopt this and dump fiat because is more cheaper to them.
I think both bitcoin and fiat has their roles to play in the future on different directions no one will kill the other.