MLS academies are all less than 10 years old, of course we're not at a certain level of youth development yet. It's growing pains. MLS is also beginning to realize that investing money at the youth level is what's really going to make the league grow to the heights they claim to want. Signing big name players is great and all (and IMO still needed), but MLS isn't going to really developing into a true top league until the clubs/league REALLY throw money into the academies. I 100% agree that the youth level coaching needs to be better, a HELL of a lot better, but I believe that MLS has lined up partnerships with the likes of the France FA to help development of youth coaches. So you can't say they're not trying.
I think, in terms of development, the real problem is the NCAA. The college soccer season is far too short, the rules aren't to FIFA standard and the NCAA's stance on amateurism really limits what an MLS club can do with their prospects w/o signing them. Not to mention by the time some leave college, they're already 22-24 years old. Players in Europe are already 6-7 year pros at that age. That's where we're really behind IMO. Though, I think with the MLS/USL partnership growing and MLS clubs investing in reserve sides (and we get better coaching), we're going to start seeing more and more top academy kids signing HGP contracts at 16-17 (or go to Europe) and bypassing college. Again, this is going to take time though. The HGP rule has only been in effect since, I think, 2009. In 7 years, the HGP rule has already seen two players get sold to the EPL (Yedlin, Miazga) and has developed numerous other international quality players for various CONCACAF sides. Not to mention there's been quite a few kids from MLS academies/affiliates who've been plucked by European/Mexican sides. You'd have to think that the more MLS throws $$$ at the academies, the more we're going to see really talented players come up trough the system.
As for those who find the league to be of poor play and a joke, that's just your opinion. Is it even close to being the best league in North America? God no. Liga MX usually blows our doors off every CCL (the gap is closing however, just not as quick as MLS likes/thinks). But that doesn't make it bad, it's just a lazy, blanket statement. It's not 2005 anymore. Trust me, I've been following MLS since 2002 and I can confidently say that MLS in 2016 is a billion times of better quality than it was 15 years ago. It deserved all the 'lol MLS is a joke' comments in the early-to-mid 2000's... now? Not so much.