Most people who aren't familiar with the artist don't get the concept. I don't see it and come away with the same feelings of a bleak, sterile god perspective of the world that you do. It may be telling that the photo doesn't speak for itself (I.e. context partially drives your reaction). Or not. I dunno, and it doesn't really matter.
It really does come down to taste. To me, a good photograph need to be interesting to look at. Interest can come from the subject itself or it can come from how a subject is portrayed (composed). The subject is uninteresting, and the composition doesn't add anything to me. Perhaps that is because I don't know what it really looks like and thus can't recognize anything particularly unique about how the scene is portrayed.
Shrug. If someone wants to pay 4million for it, have at it; it's no skin off my back.
I think it's one of his less interesting photographs, too, but it's paradoxically interesting among his photographs for being the most extreme in terms of coldness and the banality of the subject. I don't think you need a lot of backstory to "get it" though. It's the Rhine on a cloudy day presented as flatly as possible. Stand up next to a full-size print and you'll feel like you're seeing a familiar, boring sight, only rendered completely symmetrical and cold (and actually very beautiful in an odd way). So the subject isn't that interesting, but to me the composition (which is exquisite, imo) is, almost because it's so composed and flat. And seeing something very "everyday" but altered in terms of presentation is striking and uncanny. There's something to this photo, but the thumbnails do it no justice!
That said, these are much more interesting to me:http://artblart.files.wordpress.com/2012/09/gursky_2-web.jpghttp://www.its.caltech.edu/~squires/gursky/pics/gursky_chicago.jpghttp://www.its.caltech.edu/~squires/gursky/pics/gursky_99cent.jpghttp://agonistica.com/wp-content/uploads/2013/05/gursky1.jpg
And, again, none are that interesting except when printed HUGE.
I would have chosen a different print, too! But the guy is the real deal and I still think this is a great photograph, just not like... the best. I do have an immediate emotional/intellectual reaction to it, though. It's not of overwhelming beauty, but I think it communicates what it needs to communicate well, and I do think it's very beautiful in a way... certainly more beautiful than anything I've seen on here, on flickr, etc.