Uh, not to be too much of an Internet nitpicker, but according to [1] there's around 168,000 gas stations in the US. That's a pretty big car-using market right there.
Numbers for China are harder to come by, a quick search yielded [2] which states around 120,000 stations in 2019.
So, extrapolating from those two data points, I still think "millions" is a bit too many-sounding.