All the things mentioned by various posters no doubt contributed to the sigh of relief issued when Ben (and Hester) left, but none of them are the reason he's no longer at the club.
Length of deal we offered in early 2020 was deemed insufficient by Brown and his camp.
We wouldn't offer the length of deal he wanted because of our concerns about his knee.
And for all the hand wringing, it’s fair enough. You don’t want to be paying a bloke big $$$ for 4-5 years when don’t think he’ll last.