The wage adjustment is worth testing with data. Japan's GDP per capita on a PPP basis is roughly $47,000 versus the US at $80,000, a 1.7x income gap. The per-capita healthcare spending gap is $14,570 vs $5,790, a 2.5x ratio. Healthcare costs outpace the income gap by a meaningful margin even on PPP terms.

The outcome data is what makes the adjustment argument hard to sustain. Japan has the highest life expectancy in the OECD (84 years) and the lowest infant mortality (1.7 per 1,000). If higher spending were buying proportionally better outcomes, the wage argument would carry more weight. The US spends 2.5x more and gets worse population health statistics. PPP narrows the gap, it doesn't close it.