That is probably true, but similarly to his odd subs frequently, I also think Ten Hag makes some strange decisions when it comes to integrating youth players into the team. Kobbie Mainoo looked really composed and decent the 87 minutes he's played this season, but for some reason Ten Hag stopped giving him cameos.
As for Iqbal, he never really got the chance, unless pre-season counts (where he actually did decent).
It may be a bit odd, but I always prefer to give the youth a chance in competitive matches. Of course this doesn't apply to every youth player, but the highly rated ones. But I guess there is probably a reason why most managers want to see how they do in training before giving them match appearances. I think that's got more to do with how they want to see their work rate, mentality and reactions to tough challenges/tackles as opposed to actual ability.
I genuinely believe Mainoo or even Iqbal could have proved to be a better option than McTominay in some matches because of their ability to evade press and because they're quite composed, Mainoo in particular. The downside with playing them is that if they make a mistake in a game, the pitchforks will be out.
However, they'll never be ready if we barely play them during critical developmental phase.