You still need luck. You are still dealing with a statistical distribution and the fact that you can make several tries doesn't negate that.With how common mobs are giving you technically infinite xp though you don't really need luck, you just need to keep trying over and over and over again until you get it
Saying that we don't need luck because we could theoricly gain infinite experience(only true if we were immortal human being) is like saying that you don't need luck to win at the lotery since if you have a job you have infinite money and you just have to try again and again.