Earlier quoted context omitted.
As a local I support this. Simply because having more smart people eventually benefits Dutch society and the long term is far more important than the short term. Usually this argument is based in some for of jealousy, but consider: an expat gives up their current life to chance it all on another, has stupendously high private costs if they want to keep up with their family and has to start all over again from scratch…
> having more smart people eventually benefits Dutch society Given that most of them don't stay for even five years[0], how does their temporary presence benefit society? [0] "80% of expat employees use the facility for 5 years or less" https://www.government.nl/topics/income-tax/shortening-30-pe...
Someone who stays a few years at the peak of above average earnings might well be highly economically beneficial even at a steep tax discount.
I don't think governments ought to compete on tax in general, but this is one where it might both be a net benefit and there is the arguable case that most tax systems are geared towards people in working age overpaying to compensate for the cost of caring for children and the elderly.
Someone who comes temporarily during working age without a discount will get the downside without the benefit.
This will be a bigger problem for the competitive ability in places with comprehensive social support mechanisms.
Given dropping birth rates, trying to offset that to be an attractive place to immigrate to may well be worth it even if most leave again - especially as long as it's profitable too.
But if your concern is that it doesn't attract people who will stay, maybe there are ways to incentivise that too. E.g. let people earn a discount where a portion does not pay out unless they stay longer.