Marketeers would be revered as sages were it not for persky consumers. They don’t follow what marketing books say and therefore make our lives and jobs difficult.
The problem is that people are irrational, irratic and unpredictable. They don’t act as marketers and theorists would expect, they do not have complete knowledge of their options before they buy (nor do they want it). And sometimes good enough is enough for them.
Behavioural economists have shown that people do things that go completely against what you would expect. Whilst you may hypothesise and research the impact of your communications you will never truly know until it is out there in the market.
And this is what makes marketing difficult and exciting at the same time.