[davidw]

My guess is that it's some kind of distribution curve.

You can certainly improve your odds via 2, 3 and 4, but some people will do all those and end up not doing well. The average person who does them all will end up a bit better-off than average, and some will end up very well off.

In other words, they help, but don't guarantee 'success'.

[moate]

Will they? Wouldn't you need to not only do them, but do them better than average? So it's not just that you need to work hard, it's that you need to be working harder than average. But also if someone was already ahead of you, they could work less than that and still wind up ahead of you.

So now, is it the hard work that determined the end result, or just the luck again?

There are tons of people right now trying really hard to do all sorts of things. Many of them will fail, for a myriad of reasons. That's the idea of "luck". You can't know which reasons will lead to your downfall, because reducing labor and life to "hard work" is so absurdly reductive it's meaningless.

Basically, your individual circumstances are your own and comparing yourself to others might be helpful but it also might not and nobody can definitively tell you one way or the other if luck is even real.