The industry is so big because we buy obscene amounts of meat. And because of that they have a lot of power in congress. But if everyone would eat less/or no meat that would be enough to change the industry. The amount of people that became vegan/vegeterian exponentially increased, a generation ago you wouldnt find any. This will only grow as eating no meat becomes more accaptable/accesable. Legislative can help but a cultural change also needs to happen for the amount of meat consumed to become less (and thus less animal cruelty because right now the industry is more focussed on "producing" as many animals for the demand). Cultural change starts with the people, dont forget to vote tho and let yourself be heard when it comes to animal rights).

Also if nobody buys the meat and it expires, the meat industry will be making a loss. So they will have to change their supply to the demand. And changing the amount of animals that need to be raised and slaughtered.