Some people inherit their wealth. What percentage of these people would be able to earn their way to the ...?

It all comes down to teaching work ethic. There are those families that are "old money" that just live off their predecessors. But then there are those like the Rockefellers, Bill Gates, or Warren Buffett, who, while leaving their children a sizable sum, have also made them be successful by their own right. It just depends on the upbringing: if they were taught to live off their money that's what they'll do, if they grew up to live off their own hard work, then they will do that.