In your estimation, is it due to the talent gap between AHL/NHL or is it a different style of play that leads to that playing disparity? I've noticed it with a couple Griffins as well.
In my opinion, it is a combination of the factors. The difference between 20 minutes a game and 10 minutes a game is the biggest factor. The biggest factor in point production is ice-time. Powerplay time is another key factor. Easier to score when you have the man advantage.
Typically if someone at the NHL level plays 18+ minutes a game minimum low end point production is 40 points. 40 is like the bare minimum expected, 50+ is what you are looking for.
Last season 74 forwards averaged 18+ minutes a game (min. 50 gp) and only 6 scored below 0.5 points per game.
Since 2010-11 only 3 players playing under 14 minutes a game broke the 20 goal mark, McGinn, Marchand, and Chimera. Chimera was the only one to do it in last 5 years.
There is also the talent gap you mentioned, but most guys scoring point per game in the AHL (if they can skate and play defensively) could fill a middle 6 role on most NHL teams.
Lack of opportunities: Generally teams only have 1-2 spots available every summer for prospects to come up. Usually on the 4th line/bottom pairing and players have to show something special to get more ice-time.
Hence even if you are getting 10 minutes a game, you generally aren't getting PP time, and playing with bottom 6 players which on most teams is filled with guys who don't have the skill to be big point producers.
So you go from 20 minutes a game to 10 (less is typical in Detroit), no PP time, teammates from other skilled players to bottom line grinders (ex Jurco playing with Ott/Glendening), and thus playing a different role (checking vs scoring) against a tougher competition (and bigger/better goalies).