“The S&P 500 trades at about a 50% valuation premium to international stocks right now”

You keep on seeing charts like this, without mentioning 2 key factors
1) much bigger weight of Tech on the total market cap in the US (32%) vs 7% in StoxxEurope600

Excluding tech, the multiple drops to 18 vs 13 in EU

2) much higher return on assets in US companies, this explains 93% of the difference

https://t.me/blanc_charts/11296