Well, it's a question of practicality and convenience, isn't it? Multishot was a really big deal during the time of the Sinarback 43 and 44, the Eyelike backs and the Ixpress 384/528 because 22megapix was the top end and if you needed something higher resolution, you could do multishot. Currently the Sinar eMotion 75H is still multishot, Hasselblad markets their current H3DII-39 MS model and you can still buy the older Hasselblad CF39MS digital back, if I'm not mistaken, eventhough they don't seem to mention it anymore. Nowadays people can get the resolution in a single shot with a 50mp or 60mp back, so eventhough the multishot will still deliver better colour resolution, perhaps many people think it's not worth the bother?