This debate illuminates the fact that form is a poor label to attribute to what is ultimately a complex network of factors.
I think the issue with many managers ia that theu reach a dead-end with their approach. They can't extract better results becaude they've reached the limits of the squad. The only thing left to do is revolutionise the squad but they are normally fired before that can bear fruit. Sir Alex was one of the few who was allowed to do that, but I don't think his poor periods were ever 'poor form'.
I think the issue with many managers ia that theu reach a dead-end with their approach. They can't extract better results becaude they've reached the limits of the squad. The only thing left to do is revolutionise the squad but they are normally fired before that can bear fruit. Sir Alex was one of the few who was allowed to do that, but I don't think his poor periods were ever 'poor form'.