Tattoos, jewelry, clothing, dental work... and still so many people went unrecognized or unclaimed. This is incredibly sad. But my best guess is for many families, it was either cost prohibitive for family members to seek out the bodies or it was a language barrier problem, or both. With the passage of years, fewer living relatives would even be around to make the effort. Today, antecedents simply wouldn't know enough about a great grandparent's life to make a connection. DNA would be the only hope. Unfortunately, it's been 107 years and bodies have disintegrated.
I also got to thinking about my own family. I have no children and a deceased husband. I have no tattoos. I do have living siblings. If I had died in a disaster back in 1912, could my closest sister identify me based on what I was wearing? Not likely. We are middle aged women and haven't lived in the same house for 40 years. She doesn't know what I wear from day to day, including jewelry. I suspect the same problems arose among many family members of Titanic victims.
Of course, now we have DNA. But we still must hope there's enough to identify, unlike so many after 9/11.