Is it the governments fault for each and every person currently in jail ? Did the system let them down too ? Maybe 3% yes, the rest are just dickheads.
Well it's like you said, education vs player responsibility or the system vs the individual.
We are all human beings with free will, no denying that.
I'm speaking merely from the NRL's P.O.V where more has to be done education wise.
Similarly offenders should be dealt with more harshly and there needs to be stronger deterrents as well. The only problem with that is the NRL/rugby league doesn't have the bargaining power because of it's lack of $$ to put the stars in its place appropriately. Therefore the players/employees have leverage over the system because the system needs them (otherwise they'll go to RU; AFL; ESL; etc)
If the NRL was making the type of dollars the NFL or NBA or MLB is. players like Todd Carney would have been sacked long ago... unfortunately he is just like the party boy from your wife's old workplace. His value as an entertainer and generator of revenue for the Roosters and the game is seen as more valuable than his misdemeanour's.
Now if Todd is so valuable to the NRL as an entertainer and revenue generator, wouldn't it be in the NRL's best interests to educate him better and resolve the real issues? If so do it, if not punt him. If the NRL continues to allow Todd Carney to be a registered player, then yes, they are letting him down because they as his employer have the responsibility to train him to be the best representative of their company.
Personally I think he's had way too many chances and it's his antics that deter people from this great game of ours. Either way the NRL has a responsibility to Todd. Either let him go or fix the real problems, and be proactive about it, so in the future, problems, with any player/club of this nature don't rise. Essentially it is rugby league's name that gets dragged through the mud, not just Todd's or the Roosters. So that is why the NRL has this responsibility, they are relenquished of this responsibility however, if Todd is released.