For the avoidance of doubt, I wasn't attempting to say that traders and bulldozer drivers are bad people or that their jobs are bad in themselves. Sometimes traders bring about financial crises, but more often they keep the markets doing their (important) job efficiently. Sometimes bulldozer operators destroy beautiful or valuable things for someone's short-term gain, but more often they clear things out of the way so that newer better things can take their place. And, yes, sometimes people do things with terrible consequences even though they're sincerely and skilfully attempting to do the best they can -- though in the case of those credit default swaps that might be a difficult position to argue.
My point was narrower: Unless you choose to define the value of an activity to be what someone gets paid for doing it, you will find that those two things diverge, sometimes badly. So measures of productivity (e.g., GDP) that just count how much people get paid are, at best, going to do a very imperfect job of capturing anyone's idea of what's worth while. Most likely there will be large systematic disagreements.
My point was narrower: Unless you choose to define the value of an activity to be what someone gets paid for doing it, you will find that those two things diverge, sometimes badly. So measures of productivity (e.g., GDP) that just count how much people get paid are, at best, going to do a very imperfect job of capturing anyone's idea of what's worth while. Most likely there will be large systematic disagreements.