Ask for evidence, not for a change of mind

Requests to reconsider get resisted on principle. Requests for evidence do not, because they are answerable and because answering them is in your child's own interest. What do people in this field actually do day to day, and who have you spoken to who does it now? What do graduates of this course earn, and where is that published? What is your plan if the field contracts?

One of two things then happens. They cannot answer, and discover the gap themselves — far more persuasive than being told. Or they answer well, and you learn that the choice is better researched than you assumed. Both outcomes are better than the argument you were about to have.