Because we have seen over six years now that Bailly does not stay fit for long, so it is relevant. And there is no style of football where Bailly is stylistically better suited to play alongside a defender like Martinez than any of our other centre halves by the way; much in the same way that you should not have a pairing that both like to sit off, you should not have a pairing where both prefer to press for the ball, certainly not in the incredibly erratic style of Bailly. Maguire isn't better suited to defending the penalty by the way, I'm not aiming this to be any kind of defence for Maguire but there is a common misconception with the type of game he is suited to and I understand why, it is due to his lack of pace quite clearly, but he actually tends to defend better higher up the pitch in a compressed team - a lot of the issues come from the relationship between centre back and goalkeeper in that regard, as we have a goalkeeper that doesn't want to leave his line in or out of possession, which has tended to highlight our lack of pace defensively in recent years, so we'll have to see how that goes throughout the season with playing a higher line more consistently.
And I've said it's nonsense because it is nonsense - in suggesting Maguire will basically be an automatic pick due to the investment made, you are saying that Varane will not play because the manager has already said Martinez has been signed to be a first choice centre back. So it is quite clearly nonsense that we are supposedly picking Maguire due to him being a massive investment, if that means casting aside Varane who was also a massive (and much more recent) investment. If we picked the team on "investments" then Martinez would be sat on the bench at Malacia would be with the u23s.
And if you're suggesting Pogba wasn't released I'd love to know what you call it when the club doesn't offer a player a new deal in the final 12 months of his deal and as such allows them to leave the club without even trying to keep them.