As a guess: small communities simply have larger variances, and we only notice the high-paying ones. (Same principle as when there's maps of rates-by-county of

As a guess: small communities simply have larger variances, and we only notice the high-paying ones. (Same principle as when there's maps of rates-by-county of something or other in the US and all those empty counties in the west stand out for being super high or super low).