On freedom of choice in consumer markets

Does freedom to choose a product to address a need works 100% of the time? Do we always know what is it exactly that we want or need?

of course, one can argue that a consumer is the one who is going to "consume", it is purely his decision on whether to buy say a PC or a MAC, a Sensodyne or a Blend-a-med, a Heineken or a Budweiser... wait a sec, what is this??? there is something else called M-a-h-o-u... hm... never heard it before, let's give it a try... what a... I'll take Heineken next time!

But is it always like this? I don't think so, more precisely I do not agree that a consumer always knows best what to use to address the need. In most cases he is, but not everytime.
Here is one example. Yesterday I was reading our Marketing book by a wonderful team of K&K, direct quote:

"Pharmaceutical firms have long focused on business markets such as doctors, hospitals, clinics and insurance providers. In recent years, however, they have recognized the need to combine this approach with extensive campaigns to build consumer awareness and demand for new drugs and treatments..."

Blow me down, does an average person know what's the difference between Sprycel and Gleevec?? How would you know whether you need one or the other with no sufficient medical education? Just because the ad told you that this product is incredible and everyone who has a CML should get it (or convince your doctor to prescribe it to you) does not mean that it will work in your case. In fact, in Canada the advertisement of any drugs as a treatment is strictly prohibited. The rationale is public safety. A product may be recalled even at the point when it was already released on the market. For some consumers it may be, unfortunately, already too late. Why would a freedom be there in the first place?