the same as the difference between a salesman that sells and a salesman that doesn't sell.
Why does one salesman outperform another?
Its the same reason why one sales copy outperforms another
When you are copywriting, you are really giving a sales presentation in print.
We are paid for our abilities as sales people not as writers. Our value is based off of our skills as a salesperson. It has nothing to do with writing.
Most of your have been studying writing and ad writing when you should have just been studying salesmanship.
Copywriting is salesmanship in print.
Become a better salesperson
Become a better copywriter