Well, Clark only ever does the full-fleged full-court press investigation of Luthor with Jimmy, Jack and Perry because 1- Lois is engaged to Luthor and he wants to stop the marriage and 2- much lower down in importance, he is mad the Planet building blew up and 3 (at same level or a bit higher than 2) they know Jack was framed.
If Luthor had not been plotting to corner Lois into marriage, he would not have bought the Daily Planet, and Clark would not have had much incentive to investigate him. So this scenario seems to work to me.
