> Presumably the dollar, if allowed to find its own level would slide
> relative to the Renminbi, ...
That assumes the RMB is also free to move. It is not; rates are government-controlled, carefully managed, not "allowed to find its own level". The Chinese line is that this is in the interests of stability. Various other governments, not least the US, have expressed fairly vocal disagreement.
That said, the RMB/dollar rate has been changing. The yuan was pegged at 8.29 to the dollar for a long time. Then they changed the formula, linking it to a currency basket instead, and it went to 8.02 or some such that day. That was in 2006 or so.
The yuan has been steadily rising ever since. Today, 6.83 to the dollar.
> so that Americans would lose some purchasing power, while U.S.
> producers for foreign and domestic markets would be more
> competitive: net transfer of wealth from wage-earners to
> manufacturers.
In the US, perhaps. Chinese would see imported US goods getting cheaper and export-based companies facing stiffer competition. Net transfer the other way?