Maybe I'm sometimes a little naive, but I completely don't get your point. The clients (students) buy academic writing services and they will be happy ONLY when the following points are met:
1. The paper is written in a perfect American English by an American-native speaker.
2. The paper uses references available for the American colleges/universities.
Maybe Ben could provide more information, but I assume the companies in the US or Canada may have no more than 15-20% of international clients (based outside the US/Canada). If I owned a writing company, I would shout "Buy American" on my home page - just to protect my customers from ESL writers who most of the times cannot do a good job. How else can you provide a good writing service if you and your writers are not based in the US/Canada?