We didn't want to sell, Sabatini tryed to rehabilitate him in the famous conference despite being mad at him. If you read it carefully you may have noticed he defended Medhi attacking his agent, he wanted him to stay,
But then something drastic happened, Benatia went bananas demanding unreasonable wages, he declined the new offer (2.5+bonus) razing the festive atmosphere surrounding the team, which is pivotal here in Rome to succeed and as a consequence the air became unbreathable, the journalists certainly didn't help too.
He had to go but we coudn't ask for €40 anymore, Bayern knew it and offered €18m. On the other plane Sabatini knew Bayern needed a CB badly and still managed to get 30, which is btw a fair price and a capital gain of €15m, nothing alarming, nice deal considering the circumstances.
The best solution would have been of course to get Manolas and ruin Benatia's career, 4 years on the bench and let's see who'll offer you more, but it was to much for our pockets, we're not Real Madrid and we already spent €30m, furthermore we didn't want to diminish our chances to win the Serie A, so we accepted Bayern's offer.
Manolas (€13m) brought fresh air, enthusiasm and wil ease into the squad with Torosidis' help. I'd rather have 25% less on the sale and a closely knit group than destroying Benatia and not winning the scudetto.
If we get Chiriches from Spurs and maybe Adnan as left back we're looking good despite Benny's departure.
Castan-Manolas-Chiriches-Astori is probably too much to ask, the equilibrium would be ephemeral since there's no one clearly better than the others.
P.s. Back in the days, from what I've heard, City hadn't offered more than €22m. Mangala was clearly your target.