Indeed, many riders on Seattle buses are middle and upper class:

From 2016 Riders Survey (http://kingcounty.gov/~/media/depts/transportation/metro/acc...):

Household Income

* < 35k/year: 25%

* 35k-100k/year: 34%

* > 100k/year: 32%

Also, 93% of the riders have access to a personal vehicle.