Simple question, you can provide a simple answer.
What has Casey Stoner done for young OZ riders since retirement?
I will answer - nothing.
But he did help many younger riders while racing (US riders come to mind) and fought for the 125cc guys to have paddock rights that they otherwise did not have.
Now as for Aussies that have helped their countrymen I suggest you look on the back of a postage stamp for the answer because the answer is very small.
Gardner - helping family
Doohan - nobody
Magoo - nobody
McCoy - runs a ride school but not tailored at international level
Bayliss - probably the most helpful but again, more localised but has used influence to get a few guys WSBK rides.
Vermuelen - not sure to be honest
Many of these guys do poke their heads in at junior meets from time to time but at the same time, one thing that the vast majority of Aussie sportsmen and sportswomen do is that they do not seek publicity for their assistance so many may well be helping far greater but we just will not know of it
Facts are that in this country we do not have a conveyor belt of racers that we had in the past so the chances to help are greatly reduced plus none of these guys made the money of a Rossi nor have the business connections, thus opportunity to help is greatly restricted anyway.
The Aussies that are 'putting back' if that is the right term are the likes of the Cudlins who run a junior race program (MotoStars) where the likes of Bayliss, Vermuelen, McCoy etc will show their faces from time to time to help the kids (source - know someone very closely involved).
Besides, why should they help (Serious question)?
Once a person retires from work, do they use their money, their skills to help people who replaced them or are they off enjoying retirement?