there are no test upon renewing a license, there is a requirement to watch a video in english language and a reaction test. You can change requirements, if you could they could change the age, the kind of idk, the price, or whatever. I guess you never solved any problem at a government office. I am 11 years in Chiang Mai and I got what I needed and sometimes I got even more.
do you understand that you can't have different requirements for driver licences? If you don't understand law then don't post! The requirements are written in the law. If you get a driver licence without showing up for tests or without doctor certificate or similar this is corruption and doesn't means it's legal.
They can't enforce anything without give people the access to social insurance and other rights. No one will give them any information until they change their Rassist laws towards foreigners.