If they're the best shooters, then why wouldn't they go shoot alongside them all and prove it? If they're not there, they certainly won't be the best. Can't win if you don't play. Take a look at every single Super Bowl. Every last one of them. How many were won by armchair quarterbacks?
The point isn't that American shooters couldn't win. Or wouldn't win. Maybe they would, maybe they wouldn't. The point is, if they don't go, then they're not even in the running, no matter how good they may be. Gotta be in it to win it, and anything else is just hot air. Is it cheap to fly over to Italy, miss work, etc, etc? No. But that's irrelevant. To compete in the world championships that's where you have to go. And if you don't compete in them, then you can't win, no matter what your abilities may be. If you really wanted to be there, really wanted to compete against the world, really thought you were the best and wanted to show and prove, you'd find a way. Guarantee you each and every single Olympic athlete has made sacrifices along their road to the Games. Because they wanted to compete for themselves and their country.