The only advantage to keeping these mediocre young players is that they can play as well as the Brazzo's of the world while making half the money. That is actually a pretty good advantage when you're trying to build a team.
I'd rather fill the end of our bench with cheap young players than expensive old ones and use the difference on wages on stars.
We'll buy it for just that or even more if he turn out to be good which is the reason why we bought him in the 1st place. For being good and helping out the team.