I just have typed "boxing ranking" in google and opened first link (Wikipedia). According to it, in cruiserweight division both fighters are in top ranking in almost all organizations. Plus the opponents they beat on the way to finals are also in the list. So I don't think they are unpopular, simply cruiserweight probably is not popular division...
But again, I see here topics with 5-10 pages of discussion about bantamweight or flyweight... Imho, fights in such weight is like "same 1-12 rounds of speedy punching exchange that are landed in block or being blocked" aka booring to watch...