Bill McKibben once wrote:

[Under the current paradigm] the most 'economically productive' citizen is a cancer patient who totals his car on the way meet with his divorce lawyer.

Another issue with GDP is that a lot of the economic activity it measures has been built with spectacular levels of private and national debt. Do we really own the alleged prosperity we have built, given it was created in debt? And that doesn't even mention the environmental debt we are creating via externalities that aren't even measured in capitalism.

It will be interesting to see how New Zealand's approach goes. It's a far more rational approach to national well being.