That's not a redefinition: when I was a kid, the definition of abject/extreme poverty was $1/day — inflation adjusted, that's the same amount.

Also, when I was I was born the entire country of China had a GDP/capita of about $6.10/day in 2011 dollars: https://ourworldindata.org/grapher/gdp-per-capita-maddison-p...

When it comes to the distribution, the best I know how to reach for is the Gini coefficient, on which measure China is better than the USA and worse than Germany: https://ourworldindata.org/grapher/economic-inequality-gini-...

There's also this chart, but I don't know what search term I would use to describe it: https://ourworldindata.org/explorers/poverty-explorer?Indica... (note this chart is in 2021 dollars, the first one is in 2011 dollars)