Wow. In Norway, there is a similar problem with the "four-year" rule, which means it becomes very hard to fire someone who has worked for an employer for over four years. Now the PhD of course also takes four years, and PhD students are employees. In practice, almost no-one claims the four-year rule following, say, the PhD and a short-term research-assistant engagement (there was a recent case where two people in Oslo did something similar, and the university settled out of court, hiring them permanently, but it was quite unprecedented), but this means that universities much prefer the fixed-term contracts to be shorter than that, again reinforcing the glut of temporary positions; but if we had the three-contract rule, quite a few people I know would have been permanently hired already.