Ed Huntress wrote:
In a free market, many more products in the supermarket
would be labeled just in liters and grams.

Not if they wanted to sell them.

I do not understand the grammar of that response. The FPLA forbids
Proctor and Gamble from selling metric-only products.



we'll finish converting to metrics, but not until it pays to do so.

Your analysis is one of the best I have seen but it omits the legal
barriers to metrication. Voluntary conversion is forbidden by law.
Companies like Proctor and Gamble want to offer metric-only products
right now. But the FPLA and other laws make metric-only products
illegal in the US.