Comment by bonzini

Demographic decay was already going on in the 90s in some countries (Italy, South Korea, Japan), and the obesity crisis in the US too. For Brexit & Trump it could have been a contributing factor, but Italy had Berlusconi in the 90s just with TV and France almost elected Le Pen (father).

That said, while I am generally skeptical of these effects, fake news are a real problem that social media has exacerbated.