And even moving past the question of free countries vs. non-free countries, those that can devote all of their national resources to a single hub airport (or a couple of them) will build nicer airports than the US, which has to cover dozens. In addition to which: airports like Doha and Singapore are a huge part of the economy of those countries - they're city-states with national airlines that depend on attracting transiting passengers. Atlanta/Delta, Houston/United, etc. don't think the niceness of the airport is important for Americans deciding where to change planes on domestic trips, and they're sadly probably right. I
may avoid Terminal 3 at O'Hare like the plague, but most people don't, and the aesthetics of the connecting hub are probably way down the priority list for people selecting an airline or an itinerary in this country. When it comes to intercontinental travel between Europe and Asia (particularly for business/status travelers) it's a whole other story.
Also, it's worth noting that in Europe and Asia cities often have domestic terminals or even entire domestic airports that basically look like bus stations (and indeed they are
bus stations, since they rarely have jet bridges). The experience of flying domestically
from Logan - nice seating, power ports, a jet bridge to board the plane, the low likelihood that you're on a bare-bones ULCC - blows the EU and most of Asia out of the water. Singapore and Doha don't have domestic airports because, again, there's no place to fly domestically from either.
Terminal E post-modernization will hold its own in terms of amenities (though maybe not size) with international terminals at SFO and LAX (America's best) and probably also with most European hubs. Even the current Terminal E has received positive comments on the travel Youtube channels I watch (honestly, all of the Logan terminals other than C do).
EDIT: Incidentally, ATL's international terminal is only about 10 years old. It's pretty nice.
Delta Air Lines | SkyMiles - ATL International Terminal & Concourse F Open House - Saturday, May 5th, was the City of Atlanta “Open House” for the International Terminal and Concourse F. Here are a few pictures of the terminal (in addition to the other great pictures that have been posted)...