I don't think they ever intended on indefinite purchases of treasury bonds. That was merely part of the con job to get people to buy into the trade imbalance and stopping the tariffs.
Politicians are nothing but con artists. They make their sales pitches, knowing full well that they don't mean anything they say. Everything's all appearances for the t.v. and public, but the backroom deals are where the real discussions and intentions are known.
I don’t know if it was all intentional the way it was set-up but I do know we have nothing preventing us now from terminating this relationship in the economic area or at least putting the brakes on in the form of trade tarrifs. Big business and politicians have gotten far too closely aligned and greed always blinds men of power. Why put the brakes on when you can rake in another X billions for your political party, yourself and your hand full of corporate buddies?