I'd like to think that instead of the lorax guilt tripping and reminding the once-ler the only promised he broke. I think he should've reminded him the man he used to be, the friends he has made. The forest he loved to live in and the way things used to be. The lorax could've convinced the Once-ler to be who he was before greed took over his life. Replant the trees, stop production of thneeds and cut his toxic family out of his life. Things would've turned out better.