For all the Under 15 parents expressing surprise to how the selection system works, your boys must be the eldest, and this must be your first time "in the big leagues".
Some advice:
Do not expect any level playing fields.
Do not expect selections numbers to marry up with team success.
Very few Coaches do not have favourites and prejudices.
It will not get any better for the next few years.
If you expect otherwise you are in for a rough few years.
Colts is a great leveller, but the odd one or two get through Colts on reputation.
Cream will rise to the top eventually.
Not making the rep team is not the end of the world. It will not harm their chances of getting a good ATAR or picking up a trade apprenticeship. They may still pick up a Wobs contract at some distant future.
In the selectors favour, I must say that some boys are simply not as good as parents believe them to be, or want them to be. This is partially due to the rose coloured glasses worn by parents and relatives, and partially because many Coaches have been giving parents inaccurate feedback about the child as they have progressed feeding the false expectations and the rose coloured bias towards their boy.