This is actually an open question, but for me, after reading Mr. Hillsborough's description of the "Ryoma Fans", it seems this phenomenon is not limited to Ryoma himself. What/why is it that there seems such an attachment to not just Ryoma, but members of the Shinsen-gumi (My sister in law loves Hijikata Toshizou--and Freddy Mercury), and other figures of that time. Is something missing from modern Japan that needs to be re-captured, perhaps?