> If wealthy people make a habit of spending irrationally they go broke.

This just isn't the case. Unless they're spending irrationally AND a large proportion of their wealth then spending irrationally is unlikely to make them go broke. And unfortunately some people have so much wealth that they can spend market-distorting amounts of money that are still a tiny fraction of their overall wealth.

The whole point of marketing, which often account for over 50% of products' budget, is direct appeal to emotional/irrational aspect of human nature.

Average person doesnt buy iphone because they need a new phone, or coke to quench their thirst.