For anyone that's played the classics like Asteroids and Space Invaders and Pac-Man, you know the drill. You keep playing until you die. The scores go up, maybe the game gets harder and faster but really there is no 'end'.
Games continued like this well into the early 80's with the Atari 2600 and I don't think there really were any games back then that had the progession today's games have.
Is this a good thing or a bad thing? I think it was more born out of the commerce of it all. See in the arcade, they didn't want the thing to end because that meant more quarters from you. At home, where you own the game, they want it to end after 5-20 hours of gameplay (for most titles) so that you will now turn around and buy the next game.
So that is, I believe, when the change happened. When the arcade made it's decline and the home computers rivalved their capability, a shift occurred in how games were made. And yet, there's a whole generation (or two) of gamers that can't even fathom a game you just simply can't beat. I wonder what I'll think of this article 20 years from now. :)