Because contrary to your assumption, it does work. Not everyone behaves like you. And simply hearing about a brand influences our collective decisions, even if no single ad convinces you.
yeah I think ads can also serve as a reminder. for example I'll typically get a pizza once a month. if i see a little caesars ad on tv it will remind me 'oh yeah I like pizza and havent one in awhile' so the task moves closer to the front of the queue. I may not end up going to little caesars specifically to get my pizza fix but I might..
