The most valuable thing humans do are nothing like that. They involve coming up with new ideas, resolving conflict, persuading people to do things, and fixing problems. No one knows how to measure this kind of work in terms of inputs and outputs and it is clear when it is happening successfully it involves a lot of downtime and extraneous communication. Also, it's often times really unclear who the key or effective people are in this kind of work even in success. So you may need ten people developing scripts -- nine of whose work is going to be cast aside-- to get the one really valuable film script. And yes, as the author points out a lot of people exploit that pretend to be doing something useful when they aren't.
The growth of this kind of work isn't a new sickness in society, it is that we need less people working like horses and we need more people doing work we can't measure the input of effort or the output of work.