The mistake here appears to be in the assumption that the public at large shares our interest.
Not by me. Several of my friends from college thought I was "weird" because I was interested in Titanic; they just couldn't understand what the fascination was with it. I certainly do not expect everyone to see Titanic the same way as enthusiasts do, especially since the event happened nearly a century ago. I guess the same thing would go for any historical event, and basically for the same reasons.
Still, if yet another film incarnation were to emerge around the centennial anniversary--and I wouldn't be surprised if one did--I'm sure another surge of interest will take off, although not on permanent basis.