JFK does seem quite dated when comparing to most European capitals, or large Asian hubs.

There are some high-standard modern terminals in the US too though.

By "most European capitals", I presume you're excluding Paris :-)

I haven’t flown into Paris recently but there are plenty of exceptions: Berlin’s not beautiful either (though it’s one of my favorite airports).

But still the standard in Europe seems higher in general than North America.

I like Berlin Tegel, but Berlin Schönefeld always seemed to me to be its low-budget brother.

Yeah I was speaking about Tegel. If you fly out of the main rotunda, it's great because every gate has its own security and bag drop so there's no long waits, even if it's busy. Schonefeld is like any other budget airport.

Somehow I manage even month-long trips with just carry-on. With the sole exception of the time I cycled from Hoek van Holland to Zürich and needed to get back to the UK in a hurry, I think I’ve not had a check-in bag drop since I was a kid.

Budget airlines in Europe often fly to airports in the middle of nowhere. So yeah, they might be more recently built.