He's still relevant because he was the voice of an era. His plays have a timeless quality about them that help them resonate with people of every time period. We study shakespeare because he is one of the most well known playwrights and thus, to not study his work would be a severe oversight.
Man vs. Man Conflict-- Much of the conflict in the novel revolves around the two gangs, the Greasers vs. the Socs, the rich kids on the other side of town.
Man vs. Self Conflict-- Ponyboy copes with grief and guilt after the deaths of Dally and Johnny.
Man vs. Nature-- Johnny and Pony rush into the fiery church to save the children who are trapped inside, and Johnny is seriously injured from a falling beam.
Man vs. Society--With their long, oily hair, the Greasers, a gang of teenagers living on the poor eastside, struggle to fit into society. For example, Ponyboy genuinely likes Cherry, but their blossoming relationship is strained by the difference in their social circles.
Answer: subjective is the answer
In Osaka, Japan and it's in the 18th centenary
hope this helps!