First off, I don't agree with the characterization that the team doesn't play four quarters. Mistakes early have stalled several drives this season: dropped passes and penalties.
We're fortunate in that our QB and coach are pretty good at diagnosing what goes on during the course of a game, and they're able to take advantage of what the defense leaves exposed. Part of it might be the reactionary nature of Garrett's offense--though I don't recall us starting quickly in games other than in 2007.
It's absolutely laughable that people try to attribute our recent success after the half to 'not-Garrett.'
By the same token, I don't see a lot of complaining about our defense playing poorly early and contributing to us getting into big holes.
In short, I think most of the talk about slow starts is posters looking for something else to complain about. If the team weren't winning most of these recent games, or, in the case of the last PHI game, putting up a lot of points, regardless, I'd be more sympathetic to the argument. As it is, I think we have limitations right now that make it difficult for us to score the traditional way, and we're making up for it with a very smart QB who's able to get our best players into favorable matchup situations that we can convert with.