Maybe but in reality there’s no actual queue into the first team. Rashford, McNair, Blackett, McTominay for example weren’t first in line when they came into the first team squad.
Most managers will pick the players that align with their style of play, not based off of hierarchy.
Rashford was only played because of the injuries and he had the luck to have LVG managing us who loves giving youth a chance.
Blackett was only used LVG wanted a left footed CB and he was rubbish, same as McNair.
McTominay was the only player that came out of nowhere and I don't really rate him.