Good post mate, but I don't think it's all about lack of work rate. It could be that they stand out due to the fact they've developed physically ahead of everyone else in their age group.
I think a problem Liverpool had in the past is they brought in a lot of yound lads from abroad. They then have to settle into a new country, develop there language skills and get used to English football. If you look at the United youngsters they brought through, they were mainly British (and still are). We also have to remember players peak at different levels. Look at Gerrard, Owen was selected for Bishop Abbey but Gerrard not viewed as good enough, look where they are now!
I know, I used work rate and team work as a bit of an oversimplification. Sometimes it's physical development, sometimes mental toughness / attitude, sometimes it's developing too early and getting overconfident. But for whatever reason, some players who are hyped to the high heavens at youth level never make it, and some that fly under the radar end up being first team regulars. And at the end of the day, it's all about making it to the first team, or at least being good enough to be sold for a decent amount.
Swarbs. Good point. I read somewhere thats whats holding back Ravel Morrison,He's blessed with talent,but he's an arrogant so and so and has tendencies to be too big for his boots.So he's not progressing due to a bad atitude.
There is no way that all the players mentioned are going to make it into the first team but like you say it's also about getting decent money for them if they are not quite good enough.
Swarbs Thats news to me. I didn't hear that one. I just heard he wasn't progressing like he potentially could have because his atitude isn't right for such a top talent.He's incredibly talented.He showed it against Liverpools under 18s.