I disagree, mainly because not everyone has access to 5* players on their transfer list with any regularity. I had to tank a few seasons to be able to get 5* players, so I seriously looked at the youth that came through my system. If the new youth is better than anything you can find on the transfer list, then buy him. plain and simple.
Look at my level 6 team and there is a $5M 18yo DC/DR I would buy. he is not the most expensive but he is up there.