They weren't good enough. He persevered for too long with some of them. Vaughan and Anichebe clearly weren't good enough but he kept Anichebe in particular in and around the first team for a long time. He can't even make the West Brom team now, Vaughan is at Huddersfield. Rodwell who he played every week cannot now make the team for the worst side in the league, likewise Gosling who he also played before he spat his dummy out.
Forshaw, Baxter, Duffy, Wallace, O'kane, Bidwell, all got run outs in the league and Europe. None were good enough. None have done anything since. O'Kane has come back to the prem but looks out of his depth.
The good ones, Rooney, Rodwell (for a period) Coleman, Barkley he played and kept them in the first team squad.
I'd buy this argument if there was a generation of previous Everyon academy players plying their trade in Europes top leagues for the likes of United, City, Chelsea etc. But it's not true, there's not one who has apart from Mustafi which Everton dropped the ball on but that can happen, we had Jags, Distin and Heitinga.
Moyes indulged too many average young players and far more than any top 6 side at the time did (how many kids did Liverpool Spurs, Arsenal, United, City and Chelsea bring through in the period Moyes was there?). It's not his fault that the players were not good enough, he gave them a chance, only a few delivered.
Martinez now has a far richer pool to pick from, but again apart from confirming Barkley in the first team as a starter he has only introduced one Everton academy player which is Tyias Browning, and he has started sporadically to cover injuries. Galloway (also covering injuries) and Stones were bought (the latter by Moyes) as players that would need refining in the academy but we're ready for the first team squad (they had been playing first team for their clubs already).
You could argue that Ledson could play instead of Barry, that with no natural number 10 that Dowell should be given a go, that Browning and Galloway should not have been dropped for Coleman and Baines. Where does it end? You don't like Moyes, I get it, but this insistence that he did nothing of any value is crazy. The youth players were not there to use as a whole, people can hysterically go on about isolated incidents 'but lad remember when he played Osman in that Sunderland game' but as a general principle the good young players we had, made it into the first team squad. The others, got a chance, but weren't good enough. This was a top 6 club not some academy finishing school. We were trying to qualify for Europe most seasons and the young players we had were not as good as the first teamed, nowhere near, which is why the likes of Osman Pienaar and even Hibbert are still in the squad.