I think you're overlooking the fact that preorders are a huge segment of the user base. We, the preorderers, have no ability to weigh bugginess into our purchasing decision. I suppose everyone could stop preordering, but the chances of that are extremely slim. Think of any AAA title, its fans, and trying to convince one of them to not preorder. Riiiight.
I've worked in software development for too many years to be so intolerant of game defects. There are always realities that impinge a developer's ability to deliver a bug-free product. Some moronic business person could look at a spreadsheet and declare a release date, regardless of the state of the product. That happens all too frequently. It hurts the end product, how its received by the public, and the developer's and publisher's reputations. However, it does provide that all-important first-month income. Sometimes the developers work their asses off, know the product isn't ready for release, and have to watch like a father sending his 18-year-old off to war as the product is thrown to the wolves by management.
Is this bad? Yeah. Should this happen with a responsible developer and publisher? No.
Is there a solution? It depends on the product. When you're in late-stage development and your product is bug-ridden (assuming your Q.A. department is skilled enough to find the bugs!), you can either: delay your release date, or keep your current date and shrink the scope of your product so that you can finish it in time.
I'm sure the dev team from F:NV had that discussion at some point. I'm assuming their Q.A. department (of ~300 people, I've heard), recognized the product was shaky. F:NV would have been very difficult to scope back, I think. The nature of sandbox games with such broad and varied quest trees means you can put yourself in a position where a major branch may have a serious problem early on, and you have to excise the entire thing, cutting out huge swaths of content. I think that would have cut to the core of what makes the Fallout games so great. Some of the defects I've heard with F:NV have sounded like engine issues, though, which should have put them as priority one, and affected the whole game. *shrug* Who knows what happened there. I wonder if Obsidian might have had some limitations placed on how they could mess with the core engine, even if it was to fix defects.
The other choice, to delay release, was probably not in the cards for them. Release in October means being under the Xmas tree for a lot of folks. Delay that a month, and you position yourself poorly against all the other AAA titles. It's also easy for that month to turn into two, or three. Business doesn't like to hear things like that, so they likely got stuck with a firm release date.
I'd love to hear a post-mortem from the developers.
In all, I'm enjoying the game thoroughly. I just updated my nvidia drivers, so we'll see if that takes care of the frame rate drop in places like Gamorrah and The Thorn.