For me, a story is the reason to play a game. If I wanted to simply have fun playing it with no strings attached, I'd play Wario Ware and other mini-game compilations all the time. (I guess the Wii is the perfect console if all you care about is gameplay. :|)
I think sacrificing story for gameplay honestly induces laziness. There's no motivation for the developer to bother with the game past making it fun for a while. I mean, why add in a deep story to draw the gamer in if all you have to do is come up with a fun formula they can play for half an hour before getting bored and putting it away for a few days? In the epics, the 40, 50, 60-hour games with the twisting storylines, etc., they have to come up with a good gameplay to story ratio that WORKS and keeps the user entertained the whole time. Not to mention the graphics, music, etc. has to be up to par. I mean, if you can't get all of them right, no one's going to enjoy it.
It's not like gameplay is sacrificed for these games except maybe Xenosaga with its hour-long cutscenes per fiften minutes of gameplay asdfdjlkfs. Obviously in order to keep the gamer playing, the game has to be good. But the game also can't look like crap nowadays or it's too hard to get into it. We expect a certain standard now. And as for music? I know I've muted a game before because of its music, or not wanted to play because I hate just one character's voice. :| So when Abby says it's a unique storytelling medium, I'm inclined to agree. It may not be a requirement in all genres these days, but more and more of them are moving toward this.
Story isn't everything--I mean I had tons of fun with LBP and I'll be the first to admit the story was non-existent there. (It apparently got a plot in the last level but lol I didn't quite get it.) I think it REALLY depends on the genre but I don't think gameplay should necessarily be the be all, end all of the industry.