That's not an example, it's a claim with no evidence to support it. Give me an example of a person who has succeeded with only luck. There are about seven billion candidates so it shouldn't be hard to select one.

James Harrison is the first example that leaps to my mind. His blood plasma contains a unique antibody which can be used to treat Rhesus disease, which seems like a near-perfect example of pure luck: neither he nor his parents nor anyone earned those antibodies in any useful sense of the word. He just coincidentally discovered that he had them. His lifetime blood donations are estimated to have treated two million children.

Now, James Harrison surely gets some credit for his. He has, after all, donated blood a thousand times, which is far better than most of us. And he made a pledge to start donating blood before he learned about his antibodies!

But a thousand blood donations, if you don't happen to have unique biology, will be multiple orders of magnitude less effective at helping people than James Harrison was, for the same effort. To find people as successful in their goal of helping others as James Harrison, you have to look far beyond "people who donate blood regularly". Perhaps Bill Gates, having become one of the richest men alive and then dedicating his life to charity, can claim to have accomplished more?

When blind luck can put some random guy in the same league as the world's top altruist, it seems unreasonable to claim that literally nobody succeeds primarily through luck or by accident.

What is really important is subjective.

So? Whatever you subjectively consider really important, you can get unlucky on those things. Also, some things like "not starving to death" or "not constantly being in pain" are subjectively important to basically everyone, and some get unlucky on these too.