Those are convincing arguments that internet has (major) downsides and bad consequences. The scale of surveillance it enables is another one. They don't prove

Those are convincing arguments that internet has (major) downsides and bad consequences. The scale of surveillance it enables is another one. They don't prove that it makes people dumber. You have to quantify and qualify people and to define "dumb". Maybe people are not actually dumber because of the internet, but the internet is very good at spreading ideas, including incredibly dumb ones, especially (because of how human beings work) those likely to cause feeling of outrage. Maybe people are not dumber, just too defenseless against the scale of bullshit they are faced with because of the internet. Maybe internet is an incredibly good tool, but strongly requires good learning / training of critical thinking and there's not enough of this yet.