Bet365 has Turkey at 10/3, and Netherlands at 3/4. It is really surprising. I would not agree with these odds. The gambling sites are under-estimating Turkey.
I've not considered this before, but I wonder if Islam plays a role here.
Islam is obviously a major influence on Turkish people, and Islam considers betting to be unacceptable behaviour... so if we consider that people often bet to support their own country, we might see a lot of Dutch people betting for the Netherlands to win, and a lot of Turkish people not betting at all. Which could skew the betting heavily towards the Netherlands, which would then be reflected in the odds that are offered.
It might be worth investigating this, if no-one has already. Are teams from Islamic nations always under-estimated in betting odds?