I don't think there's any point in sacking him and he's not the main reason we're in this mess but the whole "there's nobody better" talk is wild. He's had one good season in the last 5. You could argue that even that was a par season (3rd place with the 3rd best budget)
I'm not sure any other Championship club would go for him. Maybe a Blackburn or Oxford? He's here because it's the best job he can get and we as a fanbase are chasing nostalgia for what he did 6 years ago.
There are loads of managers who have achieved more in recent years. Wilder isn't a bad manager by any stretch but now he's just a lower end Championship manager at best. If he left us today, he'd most likely be looking at a L1 club for his next job.
He did a good job last season and I would have kept him in the summer. His recent record suggests his best days are well behind though and there's no evidence to suggest he will get us out of this.