Total US retail sales are over $700 billion per month, which is more than twice what Amazon does in a year. Amazon isn't even #1 in the US; that prize belongs to Walmart.
Both facts could be true, if the previous post was referring to the cardinality of sales not combined value and the average Amazon sale is lower than the average sale overall.
The average Amazon sale would have to be ~25x lower than the overall average, seems rather unlikely. Not to mention that counting sales only makes sense within a product category.
60% may be true in some random product category, but clearly not across all of retail. Maybe that’s what’s being remembered, but missing the surrounding context.
It might be a sign flip of their share of online sales. They account for about 40% of online sales (yes, in-person retail still vastly outweighs e-commerce), so 60% of online sales are not Amazon.