If, buts and maybes. For you, yes it might just be the last 2 seasons but there were many of us who could recognise the pattern of failing and warned of the degradation of our quality and ability years before Ange ever appeared.
Again I'll say to you sacking the manager at any time is not a solution. That is just putting a bandage on a severed arm. If you make the correct decision in the first place then you don't need to sack the manager. Our concern should be with the initial decisions and the rationale that led to them rather than trying to fix something that is already broken, why not try and not break it in the first place and Levy post 2016 was actively breaking this squad.
We reached 2016 now? that's exactly my point. What degradation of squad years before Ange? Conte got 4th with that squad and was 4th when he (for personal reasons) imploded.
I disagree re sacking manager, you can't expect to get it right every time, proper leadership isn't being perfect, it's recognizing mistakes early and correcting, and correcting twice/three times until you get it right.
And it's not if, buts and maybes. No one (and I include you in that) believes if we fired Frank in November, brought in RDZ, gave him 3 players in January, believes we would have finished 17h. That in itself tells us the issue wasn't just some inevitability of 6 years ago, it was driven by bad decisions in the last 2 years.