i think main thrust, you are right that the numbers are less extreme than i had recalled. SF (which i imagine is the top end) is $31-$47 range or so. i see lower ($25) for greyhound than you do, but frankly that seems unreasonably low so i think “salary.com” is not giving me solid numbers there.
Indeed shows an active listing in SF for Greyhound for the same amount as Seattle. Greyhound appears to have a single national salary scrolling through different cities. https://www.indeed.com/m/viewjob?jk=ad2e68b167688669