Or worse. There's no proof, because it's impossible to prove if we'd have done better or worse without Kane but the fact of the matter is, Kane's goals to games ratio tells you that we have a higher chance of winning a game with a player of his quality in the side than out of it. The same applies to every team, Chelsea with Hazard, Utd with Pogba, Barca with Messi... These teams may still win games without such players but they still have a better chance of winning more games over the course of the season with them. Just look at Real Madrid post Ronaldo...