why is this even a rule

Of all the games of chess out there has anyoe ever seen a game were it's drawn by the 50move rule.

I could go look one up in my database, except that I'm lazy.

I've never seen one in person, but I've played over some that ended that way.  If I remember it was in one of those infamous R vs R+B endgame.  After rotating between the Cochrane defense (worth knowing as it's pretty easy) and the 7th rank defensive idea a couple of times, finally the weaker side blundered and had fallen into a losing position (this is why the draw itself is anything but easy) ... except it was move 52 since the last pawn had come off so he was saved

I bealive there was a game drawn by the 50 move rule in grand master play! Karpov and Kasparov weren't on speaking terms.

Take a look at Nikolic vs. Arsovic, Belgrade 1989.  269 moves.  I believe that the rule at that time stated 100 moves.

[EDIT:  The 50 move rule at the time this game was played had exceptions.  100 moves was allowed for Rook + Bishop vs. Rook]

Otherwise the stronger side in an ending would play forever trying to win. Almost anyone could figure out how to mate in winning  endgame positions given 1000 moves with enough time put into it.

50 moves is good for the B+N vs lone K ending.. if someone doesnt know it then the opponent could still draw.

if there wasnt a rule in place then eventually they would find a win, so the lone K side would just resign at the start