If I'm counting right, that brings us back to Poch's first season. It all kicked off for him around the tenth game (I think the Harry free kick against Villa?).
Maybe it all kicks off for Postecoglou in his 50th game, i.e, by October. You have to account for the disparity in quality - Poch was, and is, a far, far, far superior coach than Postecoglou is, so could accomplish more in less time.
But, truth be told, it's not about Postecoglou. He's a mediocre journeyman doing a roughly average job with what he has.
It's what he has that is the problem. Take off Johnson, bring on Odobert. Take off Maddison, bring on Timo Werner.
Games are simply not won with that level of quality. And it will not change as long as we are run the way we are.