I think I'd phrase it as you need work and luck.
The vast majority of people in the US are healthy and the environment in the US is the most conducive in the world to success. Stop making excuses.
I'm happy to tell you the good news that the overwhelming majority young adults in American are not suffering from debilitating health problems nor have their lives been saved by incredible emergency care.
I think it depends on what is success. It's at least arguable about the us being the most conductive to success. We have less regulation in a lot of ways than other western countries, but if you have troubles, like say a car wreck that hurts you, it sucks to be in the us compared to say germany. In the us, there are a lot of built in advantages for the existing successful companies, it's harder to challenge. For example there are few large internet providers. But at the same time, there are many more new startup companies here, and there seems to be much more risk tolerance.
Getting in the game is a choice you make.
After over 30 years of work, and business, I have become vastly more tolerant and understanding of those who were diligently "out there swinging" until it broke them, and sometimes their families too. There comes a point where anyone will break.
What of those who were swinging improperly due to their year of birth and graduated during a recession? The effect of taking something when jobs are not available can lock them into poorer quality jobs for decades. Earnings for some never catch up over a whole career, at least according to some studies. Potential employers only take interest in your previous role, and current salary, so this isn't unduly surprising.
Of course you have to be "in the game", but the effects of your swings, regardless of how many, are often outwith your control.
If you are lucky enough to make that choice ;-)
Yes persistence pays, but however unpopular it might be around here, we are nearly all one or two rolls from disaster - be that business failure, major illness, or whatever, that can easily escalate into life ruining proportions.
I am far less inclined to simply spout "work hard and make your own luck" now than I would certainly have done in my 20s. Thirty more years of experiencing life, and seeing what sheer luck, good and bad, has done to friends, family and their businesses has changed my perspective on luck quite dramatically.
You need hard work and luck.