Interestingly enough, around 2800 people were killed in 747 tragedies, slightly larger than the victim count for the Titanic. But I guess losing that much in one go is much more historically significant.
But losing 583 people in the worst aeroplane crash in history, the Tenerife airport disaster, is a huge amount. JAL 123, another 747, was the loss of 520 people, the worst loss of life involving one aeroplane. Those two accidents alone are over 1,000 people.
The 'historical significance' of the Titanic is that people
think it was a display of 20th century arrogance, with the claims that it was unsinkable. No such claims were made public by White Star and it was only after the accident that the chief of White Star admitted that he himself
thought the Titanic was unsinkable. But he never actively ascribed those qualities to the ship during its service. Of course, it's with hindsight that we see the capacity for enough lifeboats not being exercised as being tragic and unfortunate on those who lost their lives but even this was not the first large-scale case of women and children first. This originated with the HMS Birkenhead in the 1850s where the chivalry of the soldiers onboard saved the lives of 193 people from a total of 643.
The Titanic was the largest, grandest and most luxurious ship of its kind at the time, and this is probably why it has been such an enduring story. A factual story, as some people of these generations find hard to believe.
Again, it would be nice to see a living replica of an Olympic-class ship, and the Olympic would be a better choice given that it was the only one of its class to sail a successful life, but sadly the mystique of the Titanic generates much more public interest. If some people didn't even know that the Titanic was real, they're hardly going to know that there was a sister ship, are they?