You are possibly misunderstanding his point. This is partially about nuances and partially about the fact that maybe everybody successful worked hard to get there, but exactly as many people did the same effort and sacrifice, just with a differentcontext and got nowhere. (Warning: slight rambling ahead, English second language)

Take X people,all the same (assume I have cloning start-up and really good sales guys. You just bought those). Make 10% of them "grit and hardworking". Are they going to do better in live than the others ? Sure,everything else is equal after all.

Now, you are probably a wonderful human being, but assume that your evil twin got a hold of the ordering form and decided, just for fun, to introduce some extra random differentiators.

Like color of skin, gender, giving some of them more starting capital, or Paul Graham's personal Rolodex. Also making some of them ignorant pricks.

Are the 10% "grit and hardwork" still gonna so bettereverything else being equal? Definitely. But is specimen 99, baseline, only grid and hardwork, do better that specimen 1, baseline, capital, Rolodex ? Maybe, maybe not.

In the real world, nothing is equal. One of the starting perks (that I share) is having a supportive family which can provide enough nutrition, protection and stimulus so your brain can mature. Another one is learning discipline and hard work. Some of us learnt them the hard way( if the mythos is legit, Musk is one of them). But we all had to learn, and if you never have the chance to learn (for example by being part of a social in which one is punished for being smart or "trying to hard") then at some point it is no longer reasonable to expect you to rise against the circumstances. The very fact that we celebrate people who do so implies we understand this on some level.

If I look on my life(reasonable amount of success), most good things came down to luck. Grant you, I worked hard on improving my luck surface and seizing opportunities once I realised this, but luck nonetheless. Hell the only reason I am not a depresssed, burnt out social outcast right now was a meeting during a train ride