Well, it all started in 1988, when Sabonis and co. destroyed the Admiral and the rest of the US kids in Seoul. That opened the door to the US bringing the best team, and that changed everything.
First of all, from a sports perspective, the US obviously wanted to win and show they were the best in basketball... by far, aka the Dream Team. Then, in 1994, Dream Team II... well, you can go to
wikipedia but the US relaxed up to the point where they lost in 2002 and 2004, so they committed to win again. Looking at that, it can go back an forth, the US will have the best talents but if they don't put the best team they can be challenged.
But the big thing isn't about sports. When the Dream Team showed up, it made NBA's business even bigger, it became global. That's why they won't go back to college kids. The under 23 rule for the US might be interesting for competitive purposes, but for every terrible injury like PG's, there are million$ or rea$on$ for the NBA to bring their players to FIBA competitions. Adam Silver had a role in the trophies ceremony, so you can bet the FIBA-NBA business will have a loooong story to go.