A Bit of Numismatic Methodology: The Early Development of US Numismatic Die Studies

Interesting.  Why did the numismatic methodology of the die study develop in the United. States, where numismatics did not have the long tradition that it did in Europe? 
John Kleeburg, LES GRANDS NUMISMATES,  Sylvester Sage Crosby (1831-1914) www.muenzgeschichte.ch/downloads/numismates-crosby.pdf
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