I hear what you're saying. I think it's a good question.
In talking about wage scarring, we're not talking about transitions to other fields of work; that is separate from what we're discussing. Wage scarring occurs when you experience unemployment fully or underemployment.
Say that you have been working at a minimum wage job for five years and can't find any other employment than that. That would be something we consider to be wage scarring; whereas, if you were to work in a different field and then switched, that would be different.