Have you been living under a rock? Because if you visit this forum, you must take notice of the front page news where there are constant news about new iPhone components being ordered by Apple, serial numbers and all that mumbo jumbo.
I'm confident there will be one, and I don't think you would want to bet a million dollars on not having one out this summer. Schiller said June. Period.
If we take a look outside the MacRumors world, you can see people label the iPhone 3G as a piece of crap despite all those Apple fanboys trying to defend it. Low battery life, no video recording. It's even on the nominee list as the worst gadget of 2009.
To announce that you are going to add some basic features that all smart phones have and say you're done for the rest of the year is just the recipe for business disaster . You need to update your products every year, Apple has one model, one cell phone manufacturer has at least 40 which is updated every year.
To put it for people who don't want to read: Apple iPhone 3G is OUTDATED hardware wise!
I read the front page, and all I took was that Apple ordered some new components (for what reason no one knows), they've ramped up iPhone 3G production (which would indicate that 1) they're going after the Chinese market, and 2) they probably won't be releasing a new phone based on the fact that they're making more of the soon to be obsolete model. If Apple were actually replacing the model they would be scaling back production, not increasing it.
Schiller said the iPhone will be updated every June - 3.0 is a software update, which is an iPhone update. So it could very well be the only update we see. I wouldn't be surprised, in fact, because I don't think Apple is ready to force the App Store into a two-tiered architecture, especially considering how vital Apps have proven to be. That type of system will take a long time to (effectively) implement, and in its implementation we would have heard a lot about it - developers need time to update their apps, Apple has to consider how to best implement the tiered system, and so forth.
You note low battery and no video recording as pitfalls of the iPhone - I agree, and yet MMS, Copy Paste, Bluetooth, Push notifications, SMS forwarding, and so forth, were all pitfalls prior to 3.0 OS being announced. Considering how long it took Apple to bother to implement these features I don't understand why you expect that they'll make a new phone and give you the rest of what you've wanted since the original iPhone was released. That's just unrealistic, quite frankly.
And as to your last comment, they
did (or will) update their product - by adding x number of new features via the 3.0 update. That's a product update. Just like Xbox 360 updated their OS not so long ago. You don't always need to release new hardware to inconvenience your customer base and strain your carrier partnerships to improve the end-user experience. Think about the updates that the 3G has already seen - did any of them warrant a new device? No. Will all the announced features of 3.0 warrant a new device? No. So why do you think you'll get a new device?
So if this perception is one I get from living under a rock I'm going to return to it, because its better than hearing all this ridiculous speculation based on absolutely no credible or even tangible evidence.

Oh, and I might add that not so long ago people said that having a carrier specific device was a recipe for business disaster... and yet... Well you know the result.