I like the exam idea but it's not really the best way to test the skill of a person. You wouldn't hold an exam for the best painter or the best sculptor. I feel like computer programming (and related jobs) in general is similar.
If you watch the TV show Better Call Saul (strongly recommend), you see him in the last episode learning that his own lawyer brother doesn't want him working at the same firm because he did an online law school, instead of going to a prestigious law school.
It is a very very ugly mentality.