I agree it's a big issue, but I would also argue that it's smaller
Even if you just take the wealthy-enough to participate group (I'd say it's roughly half of the eligible pool based on the income levels of the kids my kids have played with), we're still at a far bigger pool than almost every other country begins with. We're certainly leaving some kids out, and we would undoubtedly be better off with them in the mix, but we have more than enough kids playing to be able to be world class.
I strongly believe that our biggest failure is the failure to cultivate the 16-22 years (especially 18-22). The pay to play situation is the clear #2 to me, and all of the other reasons are far smaller than those 2. If we address those 2 situations, I think we could be a world power in a decade.