Why are there so many frickin' sequels?

One might consider Justin McElroy's latest Get the Sugar post a rant. We would agree. But if you read past his frustration, which can also be interpreted as condescending, Justin has an interesting theory about video game sequels.
In a nutshell, Justin suggests that it all comes down to marketing, that is, the industry is to blame. Okay, nothing revolutionary about that thought, but bear with us here...

Justin believes that it's all in the package—the box art. The gaming industry doesn't bank on names (i.e. developers,
art directors, writers, voice actors, etc.) to sell games—at least, the everyday consumer won't see these names anywhere on a retail game box. So in order to sell games, publishers must rely on game titles alone. But in order to sell your product to a casual gamer, you've got to hit them with a sequel. In other words, when a consumer sees, to use Justin's example, Ghost Recon 2: Summit Strike, "the buyer can say, 'Hey, I've had an enjoyable experience with this title before, I'm looking forward to more of the same.' Purchased." Thoughts?

[Thanks, Justin]