I'm not sure that the perception that we have continuous improvement is all that helpful. For one thing there are so many dimensions to improvement, and some of them are probably competing. To try and chase them all we will probably just line ourselves up for some break-down of some-sort.

I think understanding what you can and can't do will be far more useful in the long-run.

Also, a note on the stockbroker example. We're talking about 'average' performance for stockbrokers in their 20s and 40s. I can quite imagine that the 'average' performance is the same. But what's the standard deviation?!