I'm well aware of the plethora of movies and other media about it. The point was that it wasn't... I suppose, "current", for want of a better word.
The Harry Potter movies came out in large part because the books were huge best-sellers at the time- ditto Twilight and Hunger Games.
But the only 'current' interest in the Titanic was the then-somewhat-recent discovery and photographing of the wreck in the late 80s, which was of some mass-market interest, of course, but nowhere near that of the novels above.
And before that, the most recent big movie about it had been Raise the Titanic in 1980.
But the point stands- as I said, there was no worldwide interest in time-traveling murder-robots before Terminator came out, there was no world-famous series of bestseller novels about a cyborg police officer before RoboCop came out, and for that matter, Zootopia too, was an all-new story, featuring all-new characters in an all-new situation.
I might be wrong about how producers work, but it seems to me that a studio could buy the rights to a small but decent comic, and have a ready-made cast, situation and even a plot, that their writers could then run with.