Yeah I know the commies like them. That's a result of GM putting all their marketing eggs in one brand's basket in the 1990s as Buick essentially represents the entirety of GM in China and over half of Buick's Chinese sales come from vehicles not even offered in the US.
Plus a few other factors including the fact that the Chinese tend to have a very negative view of the Japanese which serious limits the ability of higher quality Japanese makes to infiltrate the Chinese market as well as Chinese domestic vehicles having all the build quality of a Yugo.
However it still doesn't explain their approach to the US market.
They abandoned their core buyers to become more youthful. Instead they wound up becoming an entirely badge-engineered brand with three models of upper price range, not particularly outstanding, quasi-crossover things with unrecognizable names that all sound the same (Encore, Enclave, Envison... same difference) and are predominantly made in Asia. They do not have a single brand exclusive model or platform. By the way, what is Avenir? Nevermind, I don't care. Nor does anyone else.
In the US Buick has lost about half of their market share since 2000 and accounts for less than 2% of the US market. The youthful crossover approach isn't working. Any market share it gives up would very likely be absorbed by Chevrolet or Cadillac. Just ax it.