With all the clamoring for Klinsmann's resignation, here's a pretty objective article surrounding the state of youth soccer in the states. It touches on some reasons why the usmnt struggles in international competition.
http://www.thecoachingjourney.org/1/post/2015/10/-the-real-problems-behind-our-national-team.html
I definitely agree with the portion on youth development and the idea that the USMNT players should challenge themselves to try to succeed in Europe. I'm less on board with the idea that MLS's setup is necessarily a problem.
As far as the youth system, I think this is where US Soccer is going to have the biggest issues reforming things. People are already up in arms at the idea of changing the age format so it goes by calendar year instead of the school year because of the "social" issues and because their little snowflake may not be so dominant anymore. But the point of youth development systems isn't to win in soccer, nor to be the best, but to give everyone the training they need to improve and US parents simply don't grasp the idea. After all, in the American systems for football, baseball, etc. every game is competitive, but those sports don't really require the same sort of mental development that soccer does.
The money issue is also a major problem, since pay for play will cut out the vast majority of our playing pool. What's more, these pay to play systems are often competitive, which isn't good for development of the player. Unifying the systems and making it about learning the proper skills is the right way to do things, but parents scream that there's no reason to do that. Ultimately the problem is that, in the American mindset, it's all about the individual, but soccer requires a collectivist effort and sacrifice by the group to succeed.
As far as the criticism of MLS, I'm going to disagree with the idea that promotion/relegation makes for a better, more competitive league or team; you know what does? Money. Large piles of money. Statistics show us this, time and time again, that when it comes to winning, spending enough money will quite literally buy you success over time. The biggest spending team in MLS right now is Toronto FC, they spent $20 million dollars, which in MLS terms is a lot; but that mighty top dollar amount wouldn't even get you into the relegation battle for the EPL, Crystal Palace spent about $19 million pounds sterling, or about $30 million US. An argument could and has been made that MLS might have better success and quality by spreading their money out more, and that's not entirely a bad point, but aside from the reserves and rookies, most MLS players make six figures, which in a league where the maximum is seven figures, that's not bad. Even the median salary (which is a good way of cancelling out outliers on the high and low levels) comes in at about $100,000 per year. Guys like Kaka and Pirlo are outliers even among the designated players (aka stars) of MLS, most of them make $1-2 million and some make only high six figure sums. However, all of this discussion ignores one simple fact: MLS does things this way because otherwise the whole damn thing collapses. NASL blew up, in no small part, because the big teams could vastly outspend the little teams and the only way to keep up was to go into debt, otherwise nobody showed up at the stadiums because they didn't want to watch one team get annihilated for 2 hours. Without a salary cap of some sort in place, MLS would collapse just as surely as NASL and then we're without a top tier soccer league again.