You can't be a successful businessman without 1) having or making something that people value (which requires skill, capital, or some of both) and 2) taking risks with your time and money instead of earning low but guaranteed income. If you don't have skills, capital, or the cash to survive when your gamble doesn't pay off (just like it usually doesn't pay off in Silicon Valley), you don't get to be a businessman. Teaching a child from a low-income family how to run a business is stupid unless you are also prepared to make a brain-dead investment in a kid with a shitty high school diploma and zero professional experience outside of a Walmart.
I have a laptop and I've had the luxury of time to learn to program. If I invest 1,000 hours in a web startup that fails, I still get to eat food from a grocery store and sleep on a bed.
As a young adult in a family living paycheck-to-paycheck (because they are paid barely enough to survive) you are not likely to have free time to develop skills - you need to be working to cover the cost of your meals, taking care of young children, etc. You don't stand a chance.
But let's say you had some free time, and you went to the (evil socialist government waste-of-taxpayer-money) public library and taught yourself some Rails and spent enough time on the Internet to get an idea of something people wanted. Already we're talking pretty implausible, but let's go with it. High school ends, and you want to dive into building this thing. But guess what? You need to eat. So you take a shitty minimum wage job and come home exhausted every day; your body physically will not let you concentrate no matter how hard you try. Game over.
You have a shitty education and no GitHub portfolio. There is absolutely no reason for a venture capitalist to believe in you, you're just another delusional starry-eyed kid who has no idea how much he doesn't know. But let's say your parents have faith, and they're willing to continue eating the cost of your room and board in their apartment because they just know you're going to make it big like Mark Zuckerberg and will be able to take care of them. You work 100 hours a week on your idea for 6 months, but it fails. It was a good idea but it turned out there wasn't a market for it, or you screwed up because you've never done this before, or you got eaten alive by competition staffed with Stanford comp sci graduates. Not only is the game over, but you've betrayed your parents, you're getting evicted, your siblings are being placed in foster care, and you're homeless.
It was pretty irresponsible of your parents to let you do that. Which is probably why "keep your head down, work hard, take what you get, and recognize ambition as sinful" makes sense to people as a religious value.
Taking risks with your time is a luxury which you absolutely do not have when you're living on the edge of not making rent. Capitalism does not allow for everyone to be an owner - the whole point is that the ability to make money resides in the hands of people with money as opposed to the collective.