A USMNT world cup championship is achievable. Even with our best athletes playing other sports, we're still a country with more than enough people to have great teams in any sport.
We just need to continue to improve youth soccer development, especially at the youngest ages, but also up through college age (it has been improving, but slowly). And we need to continue to improve our methods of identifying potentially great players very young (4-5 years old, even younger). We're perhaps getting better at this, but have a long way to go.
We need to do more to ensure that our youth development systems focus almost exclusively on individual skill development until the kids are old enough to more rapidly understand and apply tactical training , which occurs roughly around age 12 or so. It varies from player to player.
In part, that's because the younger the kid is the better their brains are at forming the connections involved in certain physical activities. But it's also about efficiency.
For example, teaching a 5 year old how to recognize the cues for when they should execute an overlap could take an entire season or two, and still not sink in very well due to the relatively poor ability to form situational abstractions at such a young age. Teaching the same thing at age 12 might take a month or so of 2 practices per week before it starts to really sink in. Teaching a 16 year old could take a 4-5 practices (which typically occur in one week).
Conversely, for kids with the requisite physical talent, it's trivially easy (and really fun for them when done right) to train a 5 year old to become confident with individual ball skills. Using the right, fun, exercises with some very light coaching and it teaches itself. But it becomes lots harder to do the same thing with most 16 year old kids. Again, because of how our brains work at different ages.
This is why our players often appear less skilled with the ball than the folks on the best teams in the world. Our players are often extremely well developed tactically, and we often win games over more skilled opponents because of tactics. But the best teams in the word are instinctively brilliant with the ball AND have the same level of tactical understanding as we do in the US.
To me, this is the single biggest failing of our youth feeder system today. It's something that's complicated by having so many so-called premier clubs, a majority of which focus too much on winning over development (which is necessary for them to keep players signing up and their parents paying that big bill).
US Youth Soccer's ODP exists to do some of this stuff. It just needs to continue to improve in methodology, scope and scale, IMO.