The same kind of people who work in the museums, work in the municipal governments of these cities. In Europe, both groups — regardless of political affiliation! — tend to believe in the "city as cultural institution." And so both groups tend to work together to craft a city whose economy is in symbiosis with "global cultural enrichment", rather than in conflict with it.
The US does not do this. Or at least, I have never seen a majority government in any American municipality be aligned in creating a "hospitality-driven city focused around cultural tourism" in the way that municipal governments in Europe are.
Also, re: "I'm sure museums in France are free for French citizen under 25 and the unemployed" — from the article:
> The Guggenheim charges students $19 (children under 12 receive free admission) and the museum maintains a pay-what-you-wish policy for everyone on Saturdays that is expanding by one hour, from 5-8 p.m.
This is not a debate about economic barriers to access. The US is equally considerate of these. This really is just a question of how much to charge the rich foreign tourists who need to get out of town the next day and so don't have time to wait for a lazy Saturday to visit the museum. American cultural sites charge these people more; European cultural sites less. I'm offering an explanation for that, specific phenomenon.