The entire article is about why the relative numbers go in the wrong direction for the richer country... and why it's stagnated like that? There's a ton of valuable economic activity happening, why is the value inaccessible to so many?
Is your claim just that "poverty exists everywhere therefore everywhere is doing equally badly" or do you dispute that comparison with other advanced countries?
If you had to be poor somewhere, would the US be your first choice? It wouldn't be mine; but it quite probably would be if I was choosing where to be rich.