$18/yr for access to most of the world.
Yet people say "No thanks. I'm sure the US is great."
People who regularly travel internationally are not a large or powerful voter base. They can be shit on without hurting a politician's career.
Also, it's not $18/year like a subscription, it's $165 upfront -- money that could be spent on gas, food, medical bills, desperately saved up for emergencies, etc. and won't provide any benefit whatsoever to their lives unless they're taking a vacation they probably don't feel they can afford financially or in their <2 weeks of vacation time.
That's never an issue from Americans when it is something they want - the country practically runs on loans.
Nearby, we've got Canada and Mexico, and up until pretty recently, you could cross over those borders with a driver's license. And both those countries are big. On the other sides we have oceans. So for most Americans, the minimum cost of an international flight is the same as the cost for a European to fly to the US ($500-$1000), and a full day's travel each way. Here on HN, we might forget that most of the population makes fucking peanuts, so keep in mind that means that for most Americans, $1000 is a lot of money. Most Americans also don't get a lot of time off, so those 2 days of travel are a significant cost in of themselves.
All told, the lack of passports amongst Americans isn't indicative of some isolationist mindset. It's just that they have no need of a passport, because they aren't taking the kinds of extremely far-flung vacations that would need one, and they know if they need one, they can just get one before their trip.
Schengen area
travelling around Europe as European is not much more hassle than moving on the US from one state to the other.
You are required to have a passport (or id) with you (as in, that’s what the law says). Even in your own country. But in your own country a drivers license is usually also sufficient.
But in practice you will almost never be asked to show any of those. In your own country, nor abroad.
https://en.wikipedia.org/wiki/Template:Supranational_Europea...
https://en.wikipedia.org/wiki/Schengen_Area
https://en.wikipedia.org/wiki/European_Union
https://en.wikipedia.org/wiki/Eurozone
Ireland and Cyprus are in EU & Eurozone but not Schengen; Poland, Hungary (and more) are in EU & Schengen but not Eurozone; Switzerland is in Schengen but neither EU nor Eurozone; Montenegro and Kosovo are in the Eurozone but neither the EU nor Schengen.
I think you just overestimate how common passports are.