haha I immediatly made the link with the 4 mil discussion (were I didn't express myself as part of the gump principle that of you don't have a nice thing to say then just don't say a thing).
But the link you make here is too tempting for me to pass.
First Disclaimer: Salgado is a master in terms of technique and he has a titanium pair in term of balls (favelas shooting).
Salgado work is way more boring to me than Gursky. Why? Because Salgado's are basically a good technique version of all the pictures that give backpackers and eco tourist a hardon. This is why I don't get along with most photog where I live (South west china) as they are either doing ethnic minorities in B&W or over saturated pin ups with poses of selfie quality.
I'm not discussing here the 4 mil. Depending on who bought it, it can be pocket change for him/her. The exact amount is not relevant to the discussion.
When this topic arises, I like to bring up Kertesz. he has in his work some Salgado and some Gursky. His bressonian work like Carrefour or Jumping Man is very good photography. But really, does it beat the iconography of Fork or his distortion period?
As said in the other topic, art is in the eye of the beholder. Some people are more about a stricking graphism than a perfect nat geo image.
There is photography and then there is painting with a camera. No need to make a fuss over it.