The rot started the moment Lerner hung a framed photograph of Martin O'Neill above his bed, and then proceeded to give O'Neill the keys to the shop, and a massive line of credit.
The rot continued when O'Neill failed in his transfer/wage policy, and got worse when Lerner hung a framed photograph of Alex Ferguson above his bed, put a love letter in his safe and hired Alex McLeish, who almost relegated the club.
The rot continues now as the club policy to slash wages has crippled the team, and put them on a crash course to the 2nd division. (Sorry I don't call it the "Championship")
Lerner, Faulkner, O'Neill, Houllier, McLeish, Lambert, and all the underachieving veterans share the blame for the state of the club.