Does Pepsi use corn syrup? Do the other soda companies? It's a little weird for them to risk their brand on making their product worse by way of risking their

Does Pepsi use corn syrup? Do the other soda companies? It's a little weird for them to risk their brand on making their product worse by way of risking their brand on throwing the whole product out. And (I am not a flavor scientist, so this is perhaps uninformed) why not just sweeten with 10% corn syrup and 90% sugar, and gradually raise the syrup ratio?