Why did it take so long to invoke the 50 move rule?

"The fifty-move rule in chess states that a player can claim a draw if no capture has been made and no pawn has been moved in the last fifty moves (for this purpose a "move" consists of a player completing his turn followed by his opponent completing his turn). The purpose of this rule is to prevent a player with no chance of winning from obstinately continuing to play indefinitely (Hooper & Whyld 1992:134), or seeking to win purely by tiring the opponent out.

All of the basic checkmates can be accomplished in well under 50 moves. However in the 20th century it was discovered that certain endgame positions are winnable but require more than 50 moves (without a capture or a pawn move). The rule was therefore changed to allow certain exceptions in which 100 moves were allowed with particular materialcombinations. However, more and more such winnable positions were later discovered, and in 1992 FIDE abolished all such exceptions and reinstated the strict 50-move rule."

From wikipedia.  Look at this game where I purposely sac my knight to claim a superior pawn structure. I was investing in my passed      a-pawn to either even the score later down the road or simply win.

This guy plays so frightened that he doesn't do anything +1 bishop for over (103 - 46 moves). The last pawn move was on 46: h5.

Perhaps he realized my a pawn was a dark square promotion and I still had a dark bishop?

There are no pawn moves or captures since move 46, yet the computer waits until move 103, instead of 96 to force a draw.

after watch the game the rule have lot of sence