I'm of the firm opinion that advertising is snake oil. But even if you do believe that advertising causes demand, it doesn't follow that we would see a signific

I'm of the firm opinion that advertising is snake oil. But even if you do believe that advertising causes demand, it doesn't follow that we would see a significant decrease in demand if advertising was gone. If advertising hypothetically increases demand by 5%, that's not going to make that much of a difference when it's gone.