They make the average consumer believe that they need something that's not necessary. And so with the society going this way, even consumer behaviour can not truly be ascertained.

Imagine a world without marketing of products that cause more harm than good.

Maybe the tax system you suggest might be able to do the job, I also think consumers should understand what they really need else the system will always be against us.

We have the most information available to us ever, yet we are stupider than ever.