It’s very unlikely to completely get rid from the government control and banks. Even if bitcoin will become mainstream and fiat will be of less demand, for sure the government will also adopt new technology that can compete with bitcoin. They will create their own digital currency and impose new monetary rules and regulations, in replace of their fiat currency, so definitely, the people are still obliged to follow the government rules, hence bitcoin will only serve as an option.

Any centralized government will not allow a decentralized currency to rule over their currency. So there’s no way that we can lose control from the government or banks, thus using bitcoin will still be seen a voluntary one.