It's sometimes hard to figure out how the A's are better than the Angels. The Angels have been better head-to-head and on paper they appear, arguably, better as well. Luckily, seasons are not determined solely by head-to-head competition nor are they won on paper.
How the Angels win head-to-head is simple. Good pitching beats good hitting, and the Angels' pitching has shut down the best hitters the A's have: Oakland's entire team is hitting .170 in the season series. On paper, the Angels' rotation is as good as, or arguably better than, the A's rotation with or without Rich Harden, while Shields and K-Rod ensure that the front end of the Angels bullpen matches anyone's, Oakland's included. (The A's have more depth, but K-Rod is the superior closer and Shields' durability is a major plus.) The Angels' lineup this year had more threats than you would have thought, with Juan Rivera having a breakout year and putting up legitimate middle-of-the-order numbers and Maicer Izturis emerging from obscurity to be a worthy top-of-the-order contributor. Vlad is a one-man wrecking crew, Howie Kendrick is a good major league hitter now, Garret Anderson even had somewhat of a resurgence, and Chone Figgins, though he doesn't get on base enough against anyone but Oakland, adds the "small ball" dynamic in the form of 50 steals.
But the A's were better in the first half, when neither team was great, and they were also better in the second half, when both teams were great. How were the A's always better? And then it hits you...
...What if a team played 162 games, only you allowed the opponent always to bat an extra time? 9 innings to their 8, or 10 innings to their 9? Would the team with an extra half-inning go 81-81? No. 83-79? No, probably more like 88-74. An extra half-inning is huge, certainly enough of a handicap to cost a team 6-7 games over the course of a season. The Angels' defense forced their pitchers to get about 28 outs per game. The Angels' obsession with "small ball," while enabling guys like Figgins to hit 50 SB, routinely made about two outs/game on the bases, leaving opposing pitchers with only 25 outs to get.
The Angels batted for about 8.1 innings/game while pitching about 9.1 innings/game, while the A's played 9.0 innings to their opponents' 9.0 innings. And that, my friends, is how the West was won.