I really don't think so. IMO, if Canada had the same system he wouldn't have been on the U18 team either. USA picks 40 kids at 15, invites them to tryout for NTDP and say 22 or 23 make it. Those kids make up almost all future international tournaments that the USA plays in while they are eligible. The WJC is just about the first time other kids can slip in and look who they picked--Ahcan: plays for head coach in college; Foley: plays for assistant coach in college; Harper: didn't see ice in Final.
Sure, its possible that a player like Chabot would have been picked. But let's just look at the numbers. Suppose Canada picked a team of 22 players at 15 from the "top" 40 players at that age. That's less than 1 first round player per team from the CHL. If Canada then funneled as much resources for 2 years as the USA does per player those players would become a pretty strong team. Players not picked wouldn't develop any chemistry with the selected players making it pretty hard in any future tryout for an international team for them to really shine (e.g., Debrincat--It was amazing he made last year's team but wasn't surprising that he didn't fit in as well as clearly lesser players who have played together. This year US didn't make same mistake of picking a 1st line player who had never played with his linemates before.).
What you have now reminds me of the old Canadian NHL All-Star teams playing the Red Army. Its ironic that the US adopted the Soviet model when they had the only amateur team that ever beat it--of course it did so by rejecting the "All-Star" mentality and picking a team of players to fill roles. If your goal is to win international tournaments at early ages, that probably is a better way than the Canadian way. Of course if winning international junior level tournaments isn't the sole focus, and producing the highest level pro players is, then the Soviet model, which picks early winners and ignores potential stars like Thomas Chabot, should likely be avoided. The US's success in many international youth tournaments (including WJC) and Canada's success in the World Championships and Olympics, is sort of a predictable outcome of the two different development models.
I think it's a huge stretch to directly correlate the NDTP and USA results at the world championships considering the myriad of factors. And the USA has been one of the top teams at three of the last four Olympics only losing by slim margins to Canada. So saying the US is successful at the youth levels but not senior level is just cherry picking small sample sizes and can't really be blamed on the NDTP program.