Isn't that sort of what Ripple and HashGraph are already aiming for, by using proprietary and centralized blockchains, hoping that commercial banks (there is no such thing as a "government controlled" bank - they are all privately owned, for profit, and loan the national currency to the government - a basic flaw in the fiat system, as it creates interest on loans, to be paid with money that does not yet exist, and requires more fiat to be printed somewhere, to cover the interest a government acrues).

I personally think that one or more global, centralized, blockchains are intersting to world leaders.

You could sort of equate it to when most of Europe went from national currencies, to a consolidated currency (EUR), which is not government controlled at the top either (as far as I know).

But I agree, that once western national banks start using Blockchain technology - then they can no longer argue against open sourced ones with any trustworthyness, since the decentralized tech will be inherently more trustworthy!

That IS when it will begin.