I think the reason is the vast change in communication technologies (i.e. the internet) in the last 20 years. People used to mostly be exposed to only the pro-v

I think the reason is the vast change in communication technologies (i.e. the internet) in the last 20 years. People used to mostly be exposed to only the pro-vax side which was available from their doctor, in person. There simply wasn't an efficient avenue for anti-vax sentiment to spread. Now any yahoo with a Facebook account can post their zany ideas. In fact, these technologies are almost tailored to spread the zaniest ideas. People are exposed to these ideas often in social media, making them believe they are also common. This breaks down the barrier which might have previously prevented people from believing in fringe ideas: they are now exposed to them frequently. As for the 'average citizen', I don't think the general public has EVER really had critical thinking or reasoning skills. I would bet only 5-10% of the population has the scientific literacy skills to really make sense of the statistics and scientific reasoning which so strongly supports vaccination. Without the ability to make sense for themselves, many are left with appeals to emotion or authority for guidance. As authority loses ground in a sea of new voices on social media, only emotion and fear (much of it unfounded) remains.