I get what Doug Belshaw writes at a big picture level, but thinking of income without the context of cost of living is not useful and maybe misleading.
To quote his quote …
People at Income Level 4 earn more than $32 a day. At this Income Level, we find thee richest billion on the planet, who work in jobs that typically require at least 12 years of education – something those on the lower Income Levels cannot currently aspire to.
If you earn $32 each and every day in the good ol' USA - you are earning $11,680 per year - $1,000 per month which is not going to go too far by my calculations.