As in Asia, majority of boss typically does not value this kind of service is "valuable" to be paid. In other word, if some media department of the company straight up to tell the boss said they need a budget for proofreading, they probably will get fired. Then the proofreading will outsource to local university intern or even via secondary school student who participate in their "make your own slogan" event.
In other times, the value of this proofreading job is just too low, not much people will accept the task when the overall income for the specific task is too low. I believe most offer like several cent per word for this kind of translation and proofread task.