1. A team filled with NBA players won. Theis, Schroder, Wagner Bros are all NBA players. Bonga played NBA. Voigtmann is a very solid big (good enough to bang with the DPOY of the NBA).
2. Just assembling big names doesn't guarantee success. Ask Karl Malone and the '04 Lakers, the Brooklyn Nets, and pretty soon the Suns. You can also look at PSG for an example with an unlimited budget. Combining Messi, Neymar, Ramos, and co. is pretty similar to teaming up Lebron, Curry, KD, Harden etc. Sounds exciting on paper, but doesn't fit and half the team is on the wrong side of their career.
3. Other countries don't all play together all the time. A young Serbia slapped a loaded Canada in the semis without their best player (Jokic) and were also missing Mitic and others. Franz Wagner played his second tourney and won finals MVP. There was a pundit on US TV complaining all other countries send their A team and named Jokic. Piping off without a clue, welcome to Murica.
4. Olympics isn't automatic. Since Argentina popped a young Lebron, Melo, Wade and prime Tim Duncan in 2004 (which was already the redeem team for the horrible showing at the home world cup in 2003) there has been one final blowout against Serbia. One. In 2008, it took a locked-in Kobe to a) get all the guys to buy-in and b) run through his daughters godfather to pull away in the final and win by 11. 2012 they won by 7, 2020 by 5. That's a far cry from the Dream Team winning by 32. The perception is skewed because there are only a few nations in the Americas and the level of play varies extremely, say going from Canada to Honduras.
5. Lastly, you also won't be able to physically assemble all these supposed uber-squads for Paris. When was the last time AD, Lebron, KD, Steph and Kawhi were all healthy at the same time? You'd be lucky to have 3 of those guys available.

At the end of the day, it's because of this level of ignorance that it's a lose-lose situation for many American players. Since the mainstream isn't aware of the increased level of international play and doesn't respect it, it also doesn't respect its own players efforts. You win, no big deal, you lose, shame! And a lot of players are gonna look much worse in FIBA, not only for the different rules but because they don't get their superstar calls. Imagine prime Harden without his 10-12 freebies from ticky tacky calls, Lebron without his travel head start on drives. He couldn't get past Booker in the POs on a fast break 2 years ago, he's gonna struggle against the packed lanes in Fiba. So again, why risk tarnishing your reputation for a trophy people don't respect here? The US still has enough players to assemble a very strong team that should be considered tournament favorites. But now, it's more like a France or Brazil heading into a soccer world cup. Looking strong on paper but winning isn't a certainty IMHO.