I wonder if you're conflating non-US carriers' Premium Economy (usually about the same size as US domestic First Class) with US carriers' "Economy plus" or simi

I wonder if you're conflating non-US carriers' Premium Economy (usually about the same size as US domestic First Class) with US carriers' "Economy plus" or similar (which is basically 4ish inches more of pitch than Economy at the same width). You can generally get the latter for a transcontinental US flight for about $200ish extra.