You make it sound like cryptographers were stumped by the problem of digital cash. In fact, the cryptography research community had basically solved that probl

You make it sound like cryptographers were stumped by the problem of digital cash. In fact, the cryptography research community had basically solved that problem; the only difference between Bitcoin and the academic constructions is that Bitcoin does not have any central bank. There were almost no cryptographers trying to find a way to remove the central bank from digital cash systems when Satoshi came along. Nobody should be surprised by that, as there is still no rigorous definition of digital cash that does not invoke a central bank or authority of some kind. Had Satoshi presented such a definition, he would have unquestionably "shown up" cryptography researchers. At best, all you can say is that Satoshi demonstrated that cryptographers were solving the wrong problem with digital cash. That, however, was not news in 2008. Cryptographers had thought that credit card payments were too insecure to make sense on the Internet; the failure of DigiCash and related efforts in the 90s proved otherwise.