The useful part of this idea (making all drugs OTC) is that the consequences are negative enough for natural selection to take effect.
That is, people who go to their drug store and buy $100 worth of methylenedioxypyrovalene are going to *die* and will not reproduce.
So, unlike most other 'remove-the-warning-labels' arguments which will simply inconvenience everyone because there are no REAL negative consequences in today's society, people will become more intelligent.
Assuming the trait 'researches drugs before taking them' has a 10% advantage over the control 'does not research drugs before taking them' trait, it will only take around 380 generations before all humans research their drugs. And because this advantage would be hardcoded into our genetic material as opposed to relying on the memory of society, it would be a true improvement.
380 generations is only like 7600 years! We should get started.