Bitcoin will come likely do not destroy the banks it may become mainstream but not that kind of mainstream.
I do not think that bitcoin is going to be used by everyone in 2022 to be honest because that are so many people.
I do think that bitcoin is going to need allot more time to accomplish something like that.
yeah 6 years is a very small timeframe to have a change in mainstream currency. bitcoin may very well be capable of challenging the current fiat but it will take years, perhaps decades for that to happen because realistically I don't see any change to come in the next 6 years. well aside from the fact that bitcoin would already be well known but not to the point that it will be used by majority