Not the best comparison generally. Rushie was ruthless in front of goal, often helped out at the back, and was rarely offside.
Hard to think of many examples where Liverpool forwards suddenly come good after a few years.
Owen, Fowler, Torres, Suarez, Salah, Mane all looked the part straight away. Firmino struggled first few months but that was a coaching issue - as soon as Klopp came in he proved his worth. Suarez in the sense that he wasn't prolific in front of goal until his 2nd full season when Rodgers came in. He was always a top player though, Nunez is just so raw as a footballer, not just a finisher.