I agree that a good salesperson manipulates people too. Instead of trying to compare how much manipulation is done by salespeople vs in ads, I think it's worthwhile to consider how the manipulation is performed.
Both ad and salesperson will probably attempt to make us feel some emotion - best case without our conscious awareness of it. The tools an expensive ad has at its disposal seem to me much more effective in evoking emotion; visual stimuli, carefully crafted music, decades of psychology research, etc.
And while we've had a chance to evolve strategies against human to human manipulation (doors, perhaps, and various subtle triggers of distrust), the ad environment is a very recent development.
Both ad and salesperson will probably attempt to make us feel some emotion - best case without our conscious awareness of it. The tools an expensive ad has at its disposal seem to me much more effective in evoking emotion; visual stimuli, carefully crafted music, decades of psychology research, etc. And while we've had a chance to evolve strategies against human to human manipulation (doors, perhaps, and various subtle triggers of distrust), the ad environment is a very recent development.