If you keep making more stuff, GDP grows by any numeraire, but if you can not make more stuff some numeraires will show a growing GDP and some a shrinking? Would that be a fair summary?

Yup, thanks for putting my unreadable stuff in understandable form. It is also possible for the PPF to expand in such a way that the GDP contracts by some numeraires but expands by others while the amounts of all products also increase, but I don't know how contrived that is. It doesn't require nonconvexity so it is not too contrived.

Here is my original gold-for-soybeans example, half-way down the diary.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman