Earlier quoted context omitted.
Aren't the poorest in society naturally always going to be the bottom 25% or so? The poorest American is still in the top 10% of the world.
The poorest American, who earns 0 dollars in his lifetime, is absolutely not in the top 10% of world income.
So you're right that the old mantra about a poor American being in the top 10% of the world is no longer true. Having made that concession, we should also recognize that the poor in the US are still much better off than the poor in a lot of other countries. That group of countries has just been shrinking over the past 30 years.
Our main societal concern should be, "How do we reverse that trend?" Because more and more of the middle class are joining the ranks of the poor, and though it's only my opinion, I don't think that will end well for us.