As for performances, Hughton's style was dubbed by many to be too negative, too defensive, too stubborn in its reluctance to change. I think these bods are tired.....they reach an age when it is too much for them to change their ways! Limitations of time and the need to survive means that time is not available to them! McCarthy, Warnock , Harris and Slade.....just too old! No offence intended Clingon pal!
Warnock 72, McCarthy and Hughton 62, Slade 60. Theory okay so far. Harris only 44. Exception to prove the rule? I think it's more to do with their limited football philosophy and being unable to adapt to a plan B. Current financial circumstances also play a role.
Roy Hodgson is 74 and got his sides playing some real attractive football right up until he retired at the end of last season. Agree it's not just about age - more down to the reluctance of many older managers to accept new footballing concepts. In the higher reaches the likes of Guardiola, Klopp and now Tuchel are setting new standards in this country, but they've done it elsewhere in Europe before. Generally, this country is behind in football management, though the standard of actual sides are higher than abroad.
I'm afraid it's much less to do with age and more to do with using a method that will get you out od the crap more times than not. And that is the starting point for many teams with limited funds and a fear of failure. it takes an extremely brave person to go for it and play flowing football with the side one has and then to build upon that with incomers. Time is needed and fans are fickle folks with no patience and owners do not have bottomless pockets. Default otion....be hard t best and run around like crazies. Not exciting but it keeps the feet under the table and fails less times.