This is true, unfortunately.
If he was just led away, waving his arms about, & taken for a pint or a curry, whenever the defence was being coached, then a bog standard defensive coach trained them to operate with the 4 best defenders in a back 4, when he came back, half his problems would be miraculously solved.
You can see from the personnel he's using now & how they play, that Jonny Evans was most likely a serious target, not a joke. He's bigger, older Garcia.
Pep is looking for total control of central defence, to do his changing tactical bidding & play like a midfield, rather than noticing we need (preferably big) fast fuckers who know how to defend & can rescue us when our attacking play gets caught out, then pass it to our better players. His fixation with midfielder defenders is actually fucking up his whole attack, who have to compensate for it & are made nervous by the extra responsibility that we have to score at least twice. We actually dropped attackers, & played extra midfield plodders, in order to pick passing defenders.
We could also do with a supreme athlete in front of them, for protection, which in itself might give him the option of playing a shit cb who is good at passing the ball, in some games.
It's a perfect storm of shite & his thinking has basically gone mad.
But, Ake for example, is fast & very good 1v1, & good on the ball, so we have already improved there. Another similar one, who is also better aerially & we are starting to get to the point where we don't have to play offsides, to save ourselves from having to run.