In theory you are correct, but there is a hitch.
Despite all the evidence to the contrary we pretend that humans are rational beings.
Sure, we are capable of rational thought, but in most situations our emotions (which are ruled by a part of our brain which is much more direct, and powerful in a sense) are what dictates our responses.

Check out Daniel Kahneman's Thinking, fast and slow.

Rational thinking requires significant effort and in most cases we simply don't bother. We often respond to the world and people around us on an emotional basis.

This is WELL known in politics (especially Trump has exploited this masterfully) in marketing and sales (crappy cars don't sell themselves with an easy loan at twice the price, you know).

Our mind has limitations that are constantly hacked by people and organisations who, either through study or simple Darwinistic survival of the fittest, know how to play on this emotional system.
Check out Dan Ariely:

https://www.ted.com/talks/dan_ariely_asks_are_we_in_control_of_our_own_decisions