Because it would simply perpetuate the current copyright system which primarily rewards the large distribution companies disproportionately to the creators, especially smaller ones, while doing little to alleviate the effects on the job market for said creatives, in fact enhancing this effect by effectively feeding even more of the value into existing license holders as opposed to those creating new works (now instead of new works with existing franchises primarily rewarding those who own the franchises, this would effectively apply to all new works, if generative AI were to become mandatory to compete).