There's a lot about American sporting culture that you're unaware of or not privy to. Unlike most of the world, we don't have a singular national sport. The NFL is the most popular, but it competes with baseball, basketball, ice hockey, soccer and individual sports for public attention and dollars. The market is crowded here, and because we have more entertainment options than most places, we tend to internalize domestic sports with a passion not given to our national teams. The Olympics, and to some extent, the World Cup are the only international events that capture our attention because they're prestigious, established events too big to ignore.
It took me awhile, but I'm actually in favor of the FIBA World Cup being the dominant tournament over the Olympics, but we're fighting an uphill battle. The Olympics is an older competition, arguably more prestigious, and it pits the best of the best against each other. Although basketball has made leaps and bounds in both participation and popularity over the last 20 years, developmentally it's no where near football when you compare the two sports on a global level. The best teams in African and Asia would struggle to finish in EuroBasket's top 16, and that speaks volumes to how far the sport has to go before we start seeing real parity. As of now, the World Cup is a watered-down version of the Olympic tournament, and that's not going to change anytime soon.