What does the William Saliba deal mean?

There's been a lot of media attention on this new kid that burst onto the scenes last season for St. Ettienne. He's been linked to Arsenal for most of the transfer window and this has led to me picking an interest in him.

William Saliba (left) tussles with Reims’ Boulaye Dia during the Ligue 1 game in April. Photograph: François Nascimbeni/AFP/Getty Image

Well, there has to be something special about this kid that has Arsenal reportedly willing to cough up what The Guardian reports as 30million euros for an 18-year-old. The article further states that the Gunners are willing to send him back on loan for another season, which raises one question;

What happens to The Other Youngsters

First of all, there's the situation surrounding Chambers, Holding, Mavrapanos and the other young defenders currently plying their trade at the Arsenal. I understand we're placing emphasis on the future and while I endorse this approach, I can't help but feel that this deal might be a little bit too much.

At the time of writing this article, there are already a couple of defenders itching to make a shot for the first team; Holding already established himself before his unfortunate season-ending injury and is expected to return stronger in the upcoming season. Chambers already established himself in a struggling Fulham side and was dubbed the club's player of the season, though he largely played in defensive midfield while Mavrapanos also made a claim while filling in at the tail end of last season and Krystian Bielik also helped his side earn promotion to the Championship. These players have more experience with the English premier league and will be better suited. William Saliba represents a gamble that may or may not pay off and I feel the funds should be invested somewhere else in the squad.
Oh well, till we meet again, stay healthy. Up the Arsenal.