China isn't buying dollars. They are are just accepting US dollars which they then convert into treasuries. The reason they have so many dollars is because of trade deficits. You could argue they should be converting the dollars into something else, for example the Japanese in the 1980s started buying US companies and properties. But the US severely restricts what China can buy. Japan had the same problem and they ended up buying useless things like the US movie industry.
It should had promoted its RMB swap lines more forcibly and with more incentives. This is why I say that the BRI was too much unorganized.
In general there is too much apathy towards their dollar dependency.
See Russia where they have been weaning off their dollar addiction. Yes I know that they are not in the same circumstances but China is too slow on doing anything at all on this.
Lets see how their Digital Yuan attempt go. The moment it stops its trials and get openly released (2022?), China should throw everything at it and remove dollars as much as possible. This means that it must also go internationally.
No more delays. Whatever happens China HAS to promote it. It doesn't matter how they convince the rest of the world.
Tie it up to the BRI deals, offer lower tariffs for the country, offer discounts on infrastructure deals, offer discounts on imports, even offer some military ToT. Doesnt matter
Wang Yi should be touring the world from day 1 and offering all sorts of incentives, carrots and sticks. Budget its promotion costs at something like at $100 bln and keep doing it for 5 yrs. China should spend big on this.
The US will eventually come for Chinese dollar holdings. Even the most useless person knows that this is coming