usually coaches can walk out of contracts easier than players. these cases depend on the compensation. in sarri's case, we even have a number stamped on him.
also, the time: we're impatient, i'm a bit fed up with this whole shitshow the press created, but complicated contracts are complicated to terminate, too. sarri to chelsea took like a month because adl wanted to make sure that sarri wouldn't take half of napoli to londongrad.
Even if the coach is willing to leave, contract is a contract, we saw just last year it took 2 months for Sarri to join Chelsea. Its not about an individual case, but its silly to dismiss the power the clubs have on the coaches they have under contract. Especially when as sought out after as Pep.