I disagree with the claim that teachers should not care what the agencies are making. The whole reason these agencies exist in Thailand with the current structures they do (a monthly percentage of a teacher's contract), unlike places like Japan and Korea and other related industries, such as international education wherein agencies will only charge a placement fee, is because of the corruption in the education system in Thailand.
There should indeed be transparency and accountability as to where and who this education budget goes to. This is tax money. If Thailand wants to hire and retain good teachers and come even close to the education quality of other countries, they need to do away with this corrupt practice.
Agencies should only be earning a placement fee. This placement fee should be publicized for the Thai public to see. These budgets should be audited by the Thai government to ensure these budgets are going where they were intended. "Kickbacks" and "nonations" to school administration will only continue to hurt social mobility of the Thai middle and working classes who cannot afford private education.