Two people can work equally hard, be equally smart and have two different outcomes. Luck/random chance did play a part. It’s even more stark when someone can not work hard at all and have better outcomes than someone who did.
If we're talking "very different", are we talking about "and one ends up a billionaire and the other penniless"? Or are we saying "and one ends up a millionaire and the other one ends up upper middle class"?
Because in general, working hard and being smart pays off, even if you're not exceptionally lucky. Yes, it takes longer than winning the lottery, but it's not like you need lots of luck or it won't pay off at all. It's more like "work hard and get 1-10 coins per year based on your effort, and each year roll 10 dice and if they all show 6, you get 500 coins".
Luck plays a role, but in watching people who are exceptionally lucky and saying "look, luck is all that matters", we're missing the millions who aren't exceptionally lucky.
Not everything "socialist" has to be extreme.