China has been engaged in a multi-decades long project of import substitution slowly moving up the value chain that is coming close to completion. There is almost nothing the US makes that China cant make too now.

At the same time they have been exporting cheap goods to the US which the US has become slowly accustomed to. Treasury purchase operations were an integral part of discounting these goods by artificially pushing down the value of the yuan. I suspect theyll try to keep this up more or less indefinitely until something snaps - they get slowly stronger and the US gets slowly weaker.

It has led to the US slowly deindustrializing and relying more and more upon artificially competitive Chinese imports.

The key feature of this strategy is the destruction of US industrial ecosystems through systematic, persistent undercutting. This is something the US tolerates because A) the frog is being boiled slowly B) US corporates have the same relationship with short term profits that an addict has with crack. In a way it's similar to the alliance the US made with the first batch of the post USSR oligarchs.

It takes 15-20 years give or take to build or destroy an industrial ecosystem while a currency can collapse in hours.

So yes, the strategy is very much like zheng he - service the US oligarchy's addiction to profit for a few decades before finally pulling out the rug and leaving the US to realize that it making an iPhone in the US will cost $3000 and you're actually all rather poor now.