And in the next 20 years bitcoin will become the single standard means of transaction in the world beyond the role of the US dollar, yuan, yen, euro and others.
That's pretty much unlikely to happen, Fiat currencies could be at it's low atm, with devaluation, inflation/hyperinflation etc and also a struggling economy due to the pandemic to make things worst, but unfortunately, it's somewhat not possible for Bitcoin to become the only (single) means of carrying out transactions; newcomers to Bitcoin are always pretty much enthusiastic to suggest that, but the reality is that the use of Fiat currencies wouldn't diminish. Bitcoin is currency of control, freedom etc, that makes it slightly different from our regular Fiat currencies, and imo, BTC works pretty fine with Fiat currencies around (when they coexist), even when Bitcoin becomes mainstream, it still would be insufficient to be the "single standard means of transaction".
This phenomenon will be absorbed by the majority of countries in the world to then take strategic steps through the regulation of their monetary authorities in accommodating the existence of bitcoin. This was created because bitcoin was able to guarantee equal trust without intervention so that it was considered fairer and safer.
The thing is, the government do not want any currency they can't control, manipulate and print as much as they want, when they want it, and having said that, Government involvement or accomodation of Bitcoin ultimately results in regulations, which then erode the control and freedom it's users are in the network for.