Aleph -- people do actually max out the cameras they are using and rightfully hope for better performance in those aspects.
I have a show up here at the National Museum where one of the photos is a slight crop from full size, printed at 1mX1.5m and the exposure was 32 seconds at f/5.6. The S2 tends to add noise and dead pixels at 125s, and while I used it for some of the images in this series, they would not have been printable to the best quality in the show.
Likewise, the resolution of the S2 is 120dpi at 1mX1.5m, which while very good quality from a bit back, is still less than half the possible resolution of the printer I use. More resolution and better long exposure performance are very important in my work, even if they might not be in everyone's. As others said, the lenses are more than capable of resolving more detail (just look at s2 files at 200% and you can tell how the lenses are outresolving the sensor).
I realize that I am probably in a minority using this camera mostly for landscape and art reproduction, but updating the resolution seems to have been something that most S users probably expected. 37.5mp was a great deal when the S2 came out, but I believe it is probably now the lowest resolution camera of all current production medium format cameras, while just being barely more than the best 35mm. Seeing how much more these 35mm cameras offer in terms of ISO and video performance, I am personally a bit baffled as to why Leica decided to try to do half-heartedly what 35mm does well, while ignoring the opportunity to blow 35mm out of the water with what it does best -- superior image quality.