The reason: the specs are simply not that good. There is that amazing 4.65" SAMOLED display which is all and good (and I do like the idea of the 720p display which the Rezound also has), but it is ultimately a PenTile display and the subpixel density is poor compared to other phones. Furthermore, yes it has 315 ppi but this is still not class leading (the Rezound is 347 ppi I believe). Other issues include the 16GB maximum memory on international non-Verizon models which is an absolute deal breaker - I have more than 40GB of music - and the plastic construction. The most glaring issue is the camera; how could Samsung possibly entertain the notion of tainting what they expect to be a flagship device with a 5MP camera which takes average shots?
Ultimately, if this is the future of smartphones, it is only so because of ICS. The phone itself is mediocre and does nothing better than any other phone on the market. The Samsung Galaxy S II, iPhone 4S and HTC Rezound are still the top tier - this one doesn't quite reach them.
Does anyone else feel this way?