I'm a Starlink user technically, but haven't had my service enabled for over 3 years. People like me might help account for this discrepancy.

Possibly a lot of those missing ones are military ones that don't want to be counted for security reasons? Just thinking

Not really. A lot of Starlink installations, like mine, are strictly for emergency backup purposes. My account stays suspended 99% of the time, but it's reasonable for them to count me as a "customer."

They are not evenly distributed though, so the density differences isn't that big for the purposes of regional geolocation.