The problem here, as is often the case, is your framing. CB has been no more a priority than an inability to finish chances. Matter of fact, the stats have been repeated to death- our goal conceding rate the last four years have stayed about the same, while our shot conversion rate have dipped this year.
Sure, while its cute to demand spending our way into the next injury free Kompany, the failure to achieve that is not proof that our CB is weak. Frankly, if you look around you'd notice there aren't that many teams with a Kompany.
Sanchez will win is more games than Virgil. That said they are both too expensive. 50 mil for a striker with none year left is ridiculous and 60 for a defender is a joke