I think it has to do with more people in the parks in general as well. Everything is crowded because there is so many people and very few options. Outside of that JC is nostalgic, even though its not the disneyland one that was touched by walt... its still a walt ride. So every book, tv show about disney parks since 1955 has had a jungle cruise picture or clip. So if youre a first time guest you want to ride it, and if you arent it still has nostalgic value. For me pirates, HM and JC are all must rides just due to memories from my childhood.
Its always been popular.. theres just more people now