I think for the common man it's much harder to avoid taxation than for rich people. I am sure many wealthy Dutch people keep money in offshore companies and the like - there might not be much need for emigration. In the end I would guess wealthy people in The Netherlands pay very little tax.

I am just a "normal" freelance software developer myself, but partly due to crazy taxation I did emigrate from The Netherlands (though other factors where part of this decision as well).

I think I must have paid close to, or maybe even over 50% tax in The Netherlands, all things considered (including city tax, VAT on products, utilities, etc...) and I also felt I got very little in return (I am sure some people feel tax in The Netherlands is fair, but to each his own).