I wouldn't confine wealth to just the billionaire class; I'd say wealth is anyone with 5 million+ USD in liquid assets (specifically, that sum of money in stocks, bonds and cash).
The poorest of the poor in the United States (that have to pay tax), make around $12K per year, and pay more in tax, percentage-wise, for their work than an individual doing absolutely nothing but passively investing in the market does (10% long-term capital gains).
There's zero political will to change this because, surprise, every senator, and most members of congress, would be shooting themselves in the foot if legislation to increase captial gains tax were passed.
There's too much focus on billionaries -- the United States population as a whole consists of many, many individuals with absurd amounts of wealth that pay next to nothing for doing nothing.
At any rate, it is what it is, the American corporate wealth machine benefits, largely, the already wealthy.