What the hell is wrong with most of you people? Why is everyone always saying they were 'paid for the score' and 'they were saving their 40/40 for FFXIII, now they'll give it 39". Just STOP. It doesn't work like that at all. Magazine reviewers, whatever the insolent and ignorant internerds may think, have honour and integrity in their reviews. I've worked on a published, well-respected games magazine and I've seen it first hand.
Games reviewers judge games on a case-by-case basis, without bias, without caring what other games they've given top marks to. If there were more 40/40 games recently, it's because there are more top-class games. The trend of more 40s more recently is what you'd expect in a growing medium - games improve as dev talent becomes more widespread, budgets get bigger and consoles more able and the games themselves are steadily improved. For instance, now an FPS has to be at least as good as MW2 to get a high score, for an action game, UC2. That show gaming's improvement, not reviewer moneyhatting. Geez.