You are dealing entirely in result based thinking, which is the worst possible way to run any football team.
Why has Pep failed to win the CL for 9 consecutive seasons? Is he a worse manager than everyone who did? No. Football doesn’t work like that.
As I see it the difference in opinion here is one of expectation. You think England not winning means England have failed.
I think the best countries in the world (Brazil, Germany, Italy) lose 80-95% of tournaments they enter, and job of the England manager is to get the side to a point where they’re good enough that they have a good chance of winning. You do that for long enough and eventually you win. That’s what will happen with City and the Champions League.
It’s an incredibly high variance competition. Luck, the draw, and unmitigated circumstances dominate.
So with that said...IMO England are good enough to win a major tournament now, which means Southgate is doing his job. They weren’t good enough quality wise or mentally in the 90s or 00s or the 10s and the managers were failing.
There was IMO major progress between the Euro final last year, where he went with the back 5 out of fear and the team clammed up for 60 minutes, and yesterday where they played well.
So I don’t feel the need to rip everything up. If he chooses to leave and they manage to get Tuchel, I won’t be unhappy, he will probably be good enough to carry on Southgate’s progress, but he doesn’t *need* to go, and there are very few genuine candidates who would do better.