My other team I follow closely, the Bengals, had a QB named Andy Dalton for 8 or so years. It was always debated whether he was good or not as he'd get them to the playoffs but then not play well in those games and, while he had his moments, he tended not to perform well on big occassions. Bengals eventually released him, drafter a new quarterback in Joe burrow and have been to a Superbowl and a AFC championship game in three years. So it worked out well. Dalton has gone on to be a reasonable backup at a number of different teams. Obviously different situations but made me think that long-term players aren't going to change and players in key positions should be accountable for results.
Even in Brooks' best year he wasn't near being the top halfback and players like Cleary, Hynes, Hughes, Cody Walker etc have all emerged and surpassed him since that season. I don't think we're going to win with him, he's just never been the player to step up in big moments even excusing him on the basis of the teams around him being so bad.
It's good for both brooks and the club if he goes.