As seen in: Deus Ex, System Shock, Duke Nukem Forever
Obviously, this isn't vaporware anymore ... it's more like corpseware, or perhaps deepcomaware. These are the saddest cases of all, because of how final they seem, dooming beloved franchises. Sometimes, with luck, there's a happy ending years later; after Ion Storm went tits up, the rights to Deus Ex passed to its publisher, Eidos, who after a half decade kicked the franchise to a different developer, who managed to do a fairly credible job with it. A similar story happened with Duke Nukem Forever, except without the credible job at the end.
The Likelihood of This Happening Again: Medium
Well, 3D Realms, the developer that refused to either shit Duke Nukem Forever or get off the pot, ran out of money in 2009. Although not the biggest delay in that saga, that set back the game another two years, and it wasn't too long ago, either. Also, the rights to poor old System Shock are still lost in the wilderness.
A fucking insurance company owns the rights to SHODAN. You just know she's going to be pissed off about that when she gets loose.
As seen in: Half-Life Anything
This probably has elements of a couple of the other items on this list. But more than anything, this scenario is marked by absolute silence from the developer, with no release dates or updates on the development progress. Nothing more than a simple statement that the game will be released "when it's done."
Finishing games before they're released is a pretty reasonable move, and it isn't, surprisingly, always industry practice. Xenogears was one of the best RPGs the PlayStation had until the halfway point, at which point it became one of the best slideshows the PlayStation had. And when we're dealing with a company like Valve, or maybe Blizzard, companies that have a habit of making outstanding, genre-defining games, we just kind of have to trust their judgment about what makes a game done.
"Relax, children. When have I let you down?"
The Likelihood of This Happening Again: Guaranteed
Well, this is happening right now. Go play your copy of Half-Life 3 and tell me I'm wrong.
One thing I find interesting is that these aren't even delays, really; no release date for Half-Life 3 (or Half-Life 2: Episode 3, or whatever they want to call it) has been promised. That silence is more telling than the lengthy development time; it implies that not only will the game not be released until it's done, but also it shouldn't even be talked about until it's done. Aside from being an amusing swipe at the video game hype industry, it's also, I think, a pretty healthy attitude for a video game fan to take.
Children and immature adults: Please spend your video game time playing video games, not reading about ones that don't even exist yet. We don't actually need previews, whether about video games or consoles or anything else. Fundamentally, it does not matter to us what the next Half-Life is about until we can play it. It does not matter to us how much grit the next whatever has before we can pick it from our own teeth. And it does not matter how powerful the next Xbox is until we can take it home and it accidentally sets fire to our house.
For more from Bucholz, check out 5 Silver Linings Now That Identity Theft Ruined Your Life and The 6 Most Overhyped Technologies.