Living in the US of America is already a success compared with most other places in the world.
Success for most people is not making a billion dollar company. Success for them is being able to raise a family, work on their own, pursue their interests and be free. In the US you can do that way easier than in the rest of the world.
Billionaires are not happier than other people. Sleeping on your job like Musk and working all the time will not make you happier. And most people will not do that if they have the opportunity, they will prefer doing things like spending more time with their family even if that means they don't get to be billionaires.
I have seen men living isolated in Winter in Alaska and they were happy, because that is what they wanted to do.
Obviously is you raise your bar so high (billion dollars) almost nobody will do it. But in the US you can actually make millions and have a freedom the rest of the world envies, if that is what you want, or maybe you want to surf all day long.
Probably if you want to surf all day long and make a billion company it is way harder, but even that is possible in the USA, like the GoPro founder proves(he also bankrupted the company extracting so much for himself).
In other countries the educative system selects early on(ten years old) who is going to be engineer or doctor, don't let you have kids (or now they want to force you to have them), have way less economic opportunities and horrible salaries, there are no self employed people, or tax you to death.
Also the optimism the USA HAS is an enormous economic advantage over Asia, Europe and Africa.
North Americans exterminated the native population living there very recently, almost in 20th century, and as a result have an enormous country with bast resources for a population that is small and young compared with Europe or Asia.
Also they attract the brightest talent from the rest of the world, that does not like to be confiscatory taxed or censored or prosecuted.
In most Europe and specially Asia most people is so old that Pessimism is part of the culture, it is an illness. Africa is young but pure chaos and extremely corrupt few places there have the peace you need to prosper working.
In Japan for example, if you have an idea on your own almost everybody will try to sabotage it. Your friends and your family, for your own good.