Your guess is as good as mine.
As much as I like Fitler and think he would make a good coach if he stuck at it long enough, Cronk is at another level.
My take is that guys like Fittler and A.Johns are the sort of bloke's that the game came easy to when they played. The longer they'd, hypothetically, coach a team the more they'd get frustrated with the lack of skills/results by the players they're coaching.... I reckon they'd be poor recruiters, looking for the flashy game breakers exclusively...
Cronk on the other hand, was never a naturally gifted player who things came easy to. Worked and studied hard and if he chose to turn his hand to coaching, might just do a decent job, I suspect would have a longer coaching career than most if he chose to go down that path... Which I doubt he will... Phil Gould was widely regarded as one of the smartest players to play top grade but his physical attributes never allowed him to reach the heights others did, but he was able to apply his insights as a 2 Time premiership winning coach