Wayne,
Let me preface my answer by saying that I'm an American that's made The Netherlands my home and lived in Europe for the last 20 years, so my answer is slightly tainted and I can't speak for The Netherlands. So you get purely my opinion for what it's worth.
There are 3 decent players now competing on the European Tour. Robert-Jan Derksen, Maarten Lefeber, Joost Luiten. Both Derksen and Lefeber are getting on in years and have won on the European Tour. Not an easy task I might add. I know them both as we share the same coach. Robert-Jan is a great guy. However to your point, The Netherlands is a tiny little place, population 16 million, football (soccer) is the main sport and the most talent goes in that direction. Golf is not open to everyone really but has been improving in the last years. What's really affected the Dutch golfers is putting. Honestly, they suck at putting. Why? The main reason is the lack of excellent greens in this country. There are many reasons for that, climate doesn't help, although that being said the UK and Ireland manage with similar climates.
That leaves one big point which is quality and skill of professional green keeping and course maintenance. Could it really be as easy as an architectural issue? Well it depends on who you ask I suppose.
So just to summarize my argument...
The Netherlands has roughly 300,000 golfers in the talent pool, in total. Of this maybe 125,000 are active and from this less than 1% have single hcps. Add to that there may be 15 great to decent courses in the entire country, 200 in total but most of you wouldn't consider anything outside of the top 15-20 worthy of walking your dogs.
Sweden on the other hand has 600,000 golfers. Denmark I'm not certain but I will take a guess and say they do so well because the golfers are surrounded by some of the most beautiful women in the world. Trust me that helps.
Holland has poor greens. A couple weeks ago there was a group visiting us from the US and the feedback they gave me was that my club had by far the best greens in the country and they played all the top courses. I admit ours our good for a links course in The Netherlands but probably running at 9-10 on the stimp max. That won't get you ready for putting at 10-12 on the tour.
Lastly yes it just comes down to talent. There is some good upcoming talent and I'd say for such a small pool to draw from the Dutch are doing pretty darn good. Don't you think?