To be fair, I'm not sure offering him to Fulham in exchange for Clint Dempsey was anything other than fucking stupid from Rodgers. He was still basically a kid at that point who I think had shown in his first season under Dalglish that he was worth persisting with (although if I recall, he did massively split opinion that season).
I think his first three seasons you saw a steady upward trajectory and he became important in 13/14. The next couple of seasons are where he really seemed to struggle and when I think a lot of the 'not good enough' shouts started.
I think maybe Liverpool spending big money on two midfielders in Fabinho and Keita has also helped his improvement too. He must have surely felt that his place was under threat in the summer of 2018.