It's funny how the current manager is always better than his predecessor...until he's sacked and the next one is better again.
That said, from the summer when we failed in the transfer market after finishing second with 86 points, there was a steady decline across the board. I don't think that book helped at all and after we thumped Everton away, it's difficult to recall 2 consecutive good performances. By the time he was sacked, we were bloody awful in most matches, the CL run apart.
Whatever Poch brought in his first 3 years, had long gone in the last two. The performances don't lie.