I only post the ones that she appears, but this one really was unnecessary!
I think Doutzen sells well, otherwise she would not have as many Vogues as she has, because she isn't the favorite model of any editor or photographer to be in one and the same publication as often as other models... Publishers have to take in consideration that the worse the cover, the worse the sales. The cover of 2007 isn't horrible but not beautiful, the cover of 2012 yes, it so bad and I think they chose her as a cover just to sell well, because only she had one photo inside magazine pages.
I saw the Vogue Paris sales in 2017 and I think it sells more and better by who is on the cover than if cover is good or bad, but if you combine a person who sells well with a beautiful cover, obvious that sales will be better , like the Gisele case that had the best selling cover of 2017, beating Rihanna (for obvious reasons has a bigger name than Gisele, but not in fashion).
Valentina (Brazilian transexual model) cover was one of the least sold and the cover is beautiful in my opinion and one of the best of 2017, Rianne cover was the one that sold the least, because for me she is still a little unknown to general public and the cover was ugly!