Why do microcontroller recruitment only require people under 28 years old?

If you have work experience, I have never heard of such a rule. If you are a novice, it is probably because your learning ability after the age of 28 is not as good as in your youth, and it will be slow for you to start over with new skills, and Their physical strength is also not as strong as that of young people who have just graduated. They cannot work overtime and the project progress is slow, which will naturally cause certain losses to the company. You must know that microcontrollers appear to be made of hardware, but in fact they are similar to programmers and require high physical strength.