Hi AssassinsMace,
In all seriousness, they benefited both ways, THE WEST benefited on cheap labor, future market and profit, the Chinese on the other hand had employment, investment and tech. The problem for the US is that the student had bettered the teacher and they are scared of the prospect of China dominating them.
I think in TPP they want a collective action to force China to accept their terms, cause individually they can't because of the size of China economy. This will be the tactic that Biden administration will be using if he win the election, the Chinese answer is the DUAL CIRCULATION strategy.