Because he doesn’t hold a majority. In the Netherlands parties must form a coalition to govern. It might be difficult to convince other parties to join the coalition given his stances. However, I do think Geert Wilders will become our prime minister. I’m very much hoping he’ll fuck up, the government will fall and a more reasonable person will take over.
In theory it is possible, in practise it is not. Indeed there are a lot of parties covering the spectrum from left to right.