Yes it is that simple, however I will admit that sometimes we make mistakes, and in those scenarios, assistant systems are good to have. However, fog doesn't just "explode out of thin air", and if the car in front of you had to emergency brake and that meant you had to emergency brake as well, then it means you were not keeping a safe distance.

I used to drive a lot. I see how close people tailgate even when they are not trying to be aggressive - and I am not surprised that this leads to crashes. But almost all of them are ignoring basic safety rules they were taught - at least here in Germany. And since in some countries (like the fascist southern states of northern america, formerly USA) a driver's license basically involves no education at all in most places, more accidents happen. I have driven on the highways of the pre-fascist southern states of northern america, and the rate of dangerous driving combined with less control over the vehicle is much higher than in the average European country.