My take on this is that the story of the Titanic has been so much a part of our collective consciousness, from the story of the sinking and its impact, to the many films about it, and especially from the discovery of the ship in 1985 and subsequent salvage operations and Exhibitions.
As a result, people are more aware of the story of the Titanic than those of other shipwrecks.
Witness: no one has ever mentioned trying to identify the bodies of the many LUSITANIA victims buried in the mass graves outside Cobh, and I don't know how many unidentified EMPRESS OF IRELAND victims were buried near Rimouski and Quebec City.
It would be like people flocking to Arlington National Cemetery to pay their respects to Ronald Reagan while he is buried in California!
Actually that is an "Apples and Oranges" statement: people know where Ronald Reagan is buried; both he and President Nixon had their libraries chosen as their final resting places.
When one goes to a place like Arlington National Cemetery it is usually with a sense of tribute to our Country and its leaders and military heroes. One, of course, can know the names of the famous persons buried at Arlington National Cemetery: Lee Marvin, Joe Lewis, President Taft, Dick Scobee and Michael Smith (Shuttle Challenger astronauts), and while they do pay tribute to persons lost in noteworthy events (the USS MAINE and Space Shuttle Challenger Explosions are noted, and likely the loss of the Shuttle Columbia, as I was last at Arlington in 2002) it is not like one has to go there to remember someone like former President Ronald Reagan.
At the Fairview Cemetery, though, are many TITANIC victims whose identities we will never know, and one can only imagine who those persons were. If the grave of Sidney Goodwin had been so water damaged that his identity would not have been known, his would be another one that people would pray for, but not know for sure.
The same as the Unknown Soldier; we know his service to the United States, but his family (if he left any descendants) can only wonder if that person was related to them.