People tend to forget G20 summits are composed of computer illiterate elderly people who don't understand the difference between a harddrive and RAM. There isn't a single politician in the G20 who has the faintest idea what a crypto currency is, much less whether it should be supported.
I think the underlying message here is bankers feared crypto and their immediate kneejerk response was to condemn it. Eventually they realized they can centralize the large majority of crypto markets inside of an institution like coinbase and buy other exchanges with pocket money, thus giving them a great deal of control over crypto markets. Then they had no reason to fear bitcoin or crypto currencies as much as they probably own many of the major exchanges.
And the exchanges which bankers do not own, they can simply have banned via regulation in countries where they do not wish an independent presence to exist. An example of this could be how americans are banned from using bitmex and many other exchanges(perhaps they are banned from using the ones bankers do not own or control).
I suspect the message in the G20 press release reflects these shifting realities. But who can say. Maybe I'm 100% wrong on everything.
You are not wrong on your reading of the situation, which is why decentralized exchanges are critical to the survival of the market, but like always the weak link will be the conversion of cryptocurrencies to fiat since a decentralized exchange wanting to offer that to their customers will have to comply with the rules imposed by governments.
But I think that we can buy time with decentralized exchanges, after that the only thing we can do is to wait for the people around the world to wake up to the scam that is going on and that we take the next step on the evolution of this market, exchanging cryptocurrencies directly for physical products and services without using fiat at all, when it happens the market will be impossible to regulate.