you guys, 2018 is going to be so rough ridin' awesome, the '17 Confederations cup we will make the finals, we are going to win both Gold Cups, make it to the semis in Copa, and win the Gold at the summer Olympics. We are about to enter THE golden age of American Soccer. 
On my way home tonight, I was thinking about the popularity of youth soccer. When I was a kid playing (late 80's/early 90's), you were really starting to see the beginnings of competitive youth soccer. There were two divisions in Topeka (Recreational/Competitive), and Rec was totally dominant. You only had one or two tryout/competitive teams.
A few years after I dropped the sport, I noticed kids all had the trappings of highly organized club soccer. Custom uniforms, bags, parents with club stickers on their cars, etc.
I guess what I'm saying is that those kids are probably now in their early 20's, which makes sense why the HSIQ folks are optimistic for 2018 and beyond because it seems like that particular generation of youth soccer, where we really saw the big boom in popularity outside of major metro areas (i.e. Topeka) will probably help elevate the overall talent pool exponentially.
I don't have data on this, just observational analysis, but it feels like we should have a huge surge of kids coming up in the next 10-20 years that should be on par with a lot of the smaller European countries (at least) just due to the sheer size of the talent pool we'll be drawing from. Even if soccer is third or fourth in overall popularity (which I'd tend to disagree with based on how the youth in the country are really drawn to it more and more every year), I think we'll be very competitive on the world stage as we move forward into the future.