Education and economic growth

Contrary to the received wisdom, Chris Dillow refers to some evidence that suggests education isn't nearly as important to economic growth as is often supposed. If I may, I'll paraphrase a couple of the points he includes in his piece as follows:

1. Rather than economic growth being a function of a good education system, mass education and particularly higher education are things countries can spend money on because they are comparatively wealthy. And having done this, it's by no means obvious these educated individuals contribute much or anything to economic growth. I'd cite myself as evidence to support this claim - being as I am reasonably well-educated but almost entirely unproductive.

2. It is enormously difficult to disaggregate the contribution education makes. With economically-successful countries, is it their school system that is the key variable - or is this merely a sign that a country that has enough rule of law that allows the government to collect taxes and stuff like that?

I don't know the answer to these questions but my prejudices incline me to believe that the role of education has indeed been over-rated. This for two reasons: I come from a long line of people who think education should be an end in itself. That this may be due to the fact I am personally economically useless is of course a possibility I take seriously. The other is, if our future economic prospects depends on the quality of our education system, we're up shit-creek without the proverbial paddle.