I understand your point. Part of your argument is that players should be picked on strong performances against adults rather than their potential based on schoolboy rugby. I would argue that Neville was originally picked for Super Rugby on potential as his performances in the Shute Shield for Manly in the early years were not that great. However this was to be expected from someone who had made a late transition to rugby from rowing. Professional rugby coaches could see that potential and took the risk. It took some time to pay off and neither the Rebels nor Reds really got the long term benefit of his development. I don't see Neville and Kellaway's journeys as being that different. I agree that Porecki could have been picked up on the basis of his Shute Shield form and I don't recall how his overseas journey played out but I assume you feel that he was overlooked.
Just suggestion some of the schoolboy talents needs to spend time playing rugby with adults and developing.
Sometimes they are picked on reputation and don't succeed.
But it is hard given money in league, money offshore, and money talks.
Porecki, I don't think he'll think he'd been overlooked it was just time and development TPN and a couple of others were selected - he simply looked at ways to get better and develop.
I was never a Kellaway fan all those years ago, I now am because of hard work to get there.