1: Tax - Having lived in both the Netherlands and the US, calculating the difference in disposable income is eye-watering

2: Consumer attitudes to spending in general: When your annual property tax bill is $40k, your kids college fees are $, flights move way down the list of top 10 costs.

3: Fewer holidays: Multiple long haul leisure trips a year definitely not the norm!

All adds up to greater spending power/lower price sensitivity for premium travel with the airlines pricing accordingly.