That is not a regular salary in the Netherlands, they are just being cheap. My first job paid 40k, in a cheaper city, 10 years ago without a university degree.

Tax brackets are progressive, with 35k you pay about 20% income tax. Expats get a 30% income tax discount for 5 years.

While salaries are low, it does have some advantages to live here. Strong employee protection (you can't get fired for example), paid leave (minimum is 20 days + public holidays), you don't work more than 40h/week, cheap healthcare, good infrastructure and public transport, paid sick/disability, unemployment benefit, welfare, state pension, etc.

It is hard to compare employment salaries. I think it makes more sense to compare freelance wages as they don't have those benefits. Freelance engineers make about 80~100 euro/hour and get some tax discount.