And you think two of Evans/Jones/Smalling will be happy to sit on the bench for 75% of the season? As if, they'd just up and leave if we bought Hummels. If you look around every club you'll see the majority of them have two experienced players (often one capable of filling in at fullback to get game time), and two young players who're gradually being phased in. 4 centre backs is completely normal yet we have 5.
Chelsea: Terry, Ivanovic; David Luiz, Cahill.
City: Kompany, Lescott; Richards, Savic; Toure.
Liverpool: Agger, Skrtel, Carragher; Coates.
Madrid: Pepe, Ramos; Varane.
Barcelona: Pique, Puyol, Mascherano; Fontás.
Bayern: Dante, Van Buyten; Badstuber, Boateng.
Milan: Bonera, Mexes, Yepes; Zapata.
Only one other team has 5 centre backs there and that's City, and they'd have shipped Toure off by now if they could've gotten decent money. And Richards is a right back, whereas all five of ours are genuine centre backs. So looking at that we already have too many...and yet you're demanding we spend £30m on another! There simply isn't enough game-time for all of them. The vast majority of teams prefer to play a midfielder at centre back (Van Bommel, Tymoschuk, Busquets, Mikel etc.) than bring in another centre back to do nothing for 90% of the season. You want a centre back just because you're fed up of having no centre backs but it only lasts for a tiny portion of the season and it simply isn't practical on any level.