I disagree. The job market for developers in the Netherlands has been improving, so these 2014 figures are outdated. Still, we see that about 55% of respondents makes over 40K.
That study is likely biased towards younger developers, given its source. This is reinforced by reports of below-minimum wage incomes, which implies internships.
But even if the figures were real, it's questionable whether we even want companies who pay (significantly) below market. If a Dutch company can't afford to pay 50K+benefits, StackOverflow might not be the right place to look for new employees.
[edit] It seems that there's some disagreement about this. The Dutch labor market for developers is highly favorable to them - demand is quite high, supply is low. Sure, there are quite a few companies who are unhappy with this, and would prefer to pay less. That is why they're advertising! They've got open positions precisely because they lose developers to better-paying companies. The current advertisers are not a representative sample.
(For non-Dutch, renting an apartment in Amsterdam would cost about 1500/month. Buying one can easily set you back 200K-250K; you'd need to earn 50K-62K just to get a mortgage. )