Im lvl 100, what is the endgame?

I got the build i want besides like one piece but failing to see a reason to keep playing. I want to keep playing, the game gameplay is good.

Why do people still play D2? i dont think its the solution for d4 but im curious why people still play it? Is just like the freedom of the itemization?

I think the solution for D4 is group finder and raids. Thats how it could be a thousand hour game.