People misremember that 2007 season. The Patriots were scoring in the 30s for the first 5 weeks. They then began pasting teams (4 games in a 5 game stretch, with a 24-20 win against the Colts sandwiched in there). After that, they put up 31 against Philly (#9 defense), 27 against Baltimore (windy night) and 34 against the Steelers (#2 defense), before screwing around against the Jets and Dolphins, and then finishing up with another 38 point game against the Giants.
What really happened in 2007 was that the Patriots faced off against the best teams on their schedule later on in the season. Combined with weather conditions become less friendly, it was expected that the numbers would fall.