Apple "computer" introductions are now a separate matter. Think about it. In the past, when Apple was (basically) the sole PPC user, they were responsible for everything - of all the PC vendors (HP, Dell et al) they were the only ones designing their own system chipset. Then, it was actually meaningful to introduce such things at major events because there was no visibility otherwise. Now - it's up to Intel, and Intel is generally responsible for and publishes the underlying technology roadmap.
You want to know Apple's "computer" roadmap? Look at Intel's published roadmap. When Intel introduced the Core Duo, you knew more or less Apple was going to introduce Core Duo machines soon after. Same for Core 2 Duo. When Santa Rosa shows up in April, you also know new MB(P)s based on that will show up.
CPU "refreshes" simply aren't important enough to warrant a keynote introduction any more - the intel imac introductions etc were different and important and warranted a macworld keynote introduction because those were the *first* intel macs. all future macs, unless they introduce something new and interesting (or if apple's product lineup has seriously run dry) are unlikely to warrant any further keynote introductions. There's absolutely nothing to stop the Apple.com home page being updated in the future with a "quiet" introduction of octo-core Mac Pros.
But right now - and I think you're seriously underestimating the significance of the iPhone introduction on the players of the phone industry - the iPhone is *it*. It really is what is worth talking about right now.
No matter what their production output is I do not believe the apple stores will be able to keep it in stock. They've staked out the high ground in terms of phone functionality, and all the other players are now left with having to basically compete on price, and higher-cost western producers - that means Motorola and Nokia et al - are NOT going to be able to compete in that space, squeezed between Apple on the top and the upcoming Chinese manufacturers at the bottom. This is a serious disaster for Nokia which has been trying for ages to become a "new computing platform" (didn't they ban their employees from calling their devices "phones"?).
the "fundamental unifying characteristic" of all phones so far has been the keypad, and Apple just decided they weren't going to play there. Considering the careful patent protection apple must have put in place, any alternative implementation of a non-keypad interface must end up being klunky as hell, and there's going to be simply no way for anybody else (and this is going to include Microsoft) to compete (bar some amazing genius in their staff who comes up with a new UI idea completely out of left field
Everybody kept saying "well MS never gets anything right until version 3.0 anyways" when they were comparing the Zune with the iPod. Well, Zune 3.0 can be the perfect MP3 player, but it won't matter, because this is the end of the "plain MP3 player" market dominance. sure they'll still continue to be sold, but the analysts who were talking about iPod sales levelling off or plunging in 2007 were, in fact, correct - but not because it's being taken over by external competition. I've dealt with windows mobile phones. they do not compare in any way with the UI of the iPhone.
The only problem with the iPhone I can think of is basically personal safety. Think of the mugging potential.