Why do the game developers slack on making worthwhile endings anymore?

I can remember original Nintendo days that games would have endings that would make it worth completing a game. Agreed most of them were cheesy but at least they gave you something. I just won the championship in NBA 2K7 with the Knicks. It showed David Lee (mind you that was the player the game chose to show) standing next to the trophy and the announcer saying congrats on winning the championship. That was it. It sucks cause they could make some great ending sequences with these new systems, especially with the sports games. Instead they just half-ass it.