I think your measure is wrong. Under the good managers we've got a lot better, under the others we've only regressed slightly. So it's a much better than 50% success ratio. If you look at managers appointed elsewhere since 2001, then outside Chelsea and Man City you will struggle to find a handful who have made any sort of improvement anywhere.The main reason we haven't achieved the same results in half the time is down to poor decisions in the wake of successful periods of development. While I don't expect Levy to get every decision right - it is unrealistic to do so - he has got too much wrong and not enough right in this regard.
Seeking to build on BMJ's progress with Ramos set us back by 3 years. Seeking to build on Harry's progress with AVB/Tim set us back another 3 years and so far we have pissed away 2 years trying to build on Poch. Allowing for 3 years to get themselves established before we accidentally stumbled into the Jol era in 2004, that's 8 sub par years out of 17. It's a lot, but broadly speaking we've still seen progress in more seasons than not. Just.
The fact that those years haven't affected us even more negatively is testament to the disproportionate achievements of our 3 strongest managers but is also down to the extent to which Levy has grown the club's global standing and reach.
That said, we are now on thin ice. If Levy gets the next appointment wrong, we'd be looking at 9-10 sub par years out of 20. And if a chairman delivers what is essentially a 50% success or progress rate, their input and expertise is equal to flipping a coin and should be heavily doubted. He has to get the next one right.
Maintaining a football club in the top 6 is hard. Getting it from mid table to the top 6 is harder still. Building the infrastructure to give a long-term edge is harder than that. ENIC have managed all three and just missed out on trophies along the way.
) but to be honest it's getting a bit boring.