As an example, the all-business SAS flight from Houston to Norway was targeted at oil company employees [1]. It couldn't fly 7 days a week because they had to take the plane offline once a week for cleaning/maintenance and there was no other all-business plane to rotate into its place. They stopped the route because the oil price slump reduced travel of oil company employees.

[1] http://thepointsguy.com/2015/10/10-unusual-things-sas-737-tr...