$21M was a typo I think.
“Most companies are in the 10-20%profit margin range.”
Err, doubtful. 10-20 is ideal, it shows you’re healthy.
$21k per minute = $10,999,756,800 per year, which is still low.
According to https://www.macrotrends.net/stocks/charts/WMT/walmart/gross-profit
“Walmart annual gross profit for 2019 was $129.104B, a 1.7% increase from 2018.”
Using that number, they’re making $245,631 in profit per minute. I think all of the numbers in the OP are suspect at this point.