I think we will see more of him next season. Like all young players his performance level can be a bit unpredictable and I think this is the reason for being used relatively sparingly. We already have Stones and Barkley who can be up and down, even within a game and in recent weeks we've had to use Garbutt too. Rom as well to a certain extent. I think the manager is concerned about having too many young players learning their trade in the same starting eleven and I think because of the presence of alternatives Besic has been the one to miss out more recently.
Realistically he probably also doesn't want to lower the value of the senior players. If we are to sell McCarthy we aren't going to get a good price for him if he has lost his place to Besic.
Ultimately football is a conveyor belt and there's a process they all have to go through. With certain players like Rom where there's nobody ahead or if the player is just THAT good it's different but mostly it takes time.
Look at the danger of making them a star too soon like with Sterling. Then they want big money and it's also very hard to attract or keep anyone to be their backup because they don't want to be backup for someone the same age.
Besic is good but he's not that good.