The value gap between a painting and a photograph

Wang Village, AnHui

The most expensive photo on record exchanged hands for US$3.9 million, I mentioned that in the last post already, I know.  This has stirred the photographer community since no photograph has ever come close to this price before, let alone a Rembrandt is worth $100 million and a Van Gogh $40 million.  The value of paintings had long been at the stratosphere because of their uniqueness.  Photographs, on the other hand, are never unique.  And no photograph is old enough that the original negative could never be recovered.  And photographs are usually reproduced in quantities, even though it could be in limited numbers.  Who knows exactly how many are circulating as the "limited edition".  
And a print of a photograph is only one rendition of the photograph --with the advancement(?) in printing technology, there could be better(?) ways of reproducing the photograph, making a print's value unpredictable.  Ctein took 3 years to figure out how to print a photo he made in 1975, and imagine he gave it another whack at printing the photo today?  What would happen to the value of the 10 limited edition prints (if there is such a batch) that had been circulating? In a sense, he wasn't cheating at the limit of the prints, as an artist, he should have the liberty to try out different ways of interpretation of the art he made.