Why distribute a third French battleship turret?

Why did later French three-turret designs move away from an entirely forward battery?

Designers feared losing all three turrets to one magazine hit, though a true magazine penetration would probably doom the ship in any layout.

The concern grows when an all-forward design expands from two turrets to three. Designers could reasonably fear that one penetration into the concentrated magazine group would remove every main gun. A 16-inch shell reaching any capital-ship magazine is already likely to destroy the ship, regardless of whether that magazine serves one, two, or three turrets. Concentrating the group may also allow a shorter length of thicker armour, so distributing magazines does not automatically improve survival.