The cost of an iPhone won't go down unless Apple's sales plummit. They are far too greedy to lower the price without them losing money. Jobs policy is My way or the Highway.... or How can I get your money?
I don't think there's much room for it to go down further... $99 is pretty freaking cheap. Yes, Apple has made huge volume here, but lets all remember that iPhone shook up the entire industry because it had massively better horsepower CPU & GPU than anything else offered at the time and 10 times the storage. And that had a real cost to it at the time.
I mean I remember the month before the iPhone was announced my boss had just set down the Blackberry "world edition " 8830 on my desk saying how awesome that phone was . And it was actually pretty cool, I thought.
Lets go over those specs...
225MHz CPU, 16MB of ram
64MB flash (granted it had an internal micro SD slot too )
16bit color 320x240 screen
1 month later comes an iPhone
400MHz CPU, 128MB Ram ( integrated GPU too )
8GB flash
18bit 320x480 screen
Wifi connectivity
Lets remember that the Razor in its latest incarnation was still the king of phones at the time, though it was plainly on its way out.
The device I was moderately excited about just a month before looked like a toy in comparison.
Apple caught EVERYONE with their pants down... phone makers, phone companies, computer companies, analysts... everyone.
Still that kind of investment they made there wasn't cheap... that hardware cost more than any phone manufacturer was willing to spend back then. Now they're all clamoring and throwing in OLED and really expensive components because they have strong competition who didn't play the "incremental upgrade" and "don't add features anyone will actually want, unless you have to " game.
Remember back in 2007 phone companies were still trying to convince the world that texting was so super important and cameras as well, as a service so that you must pay for it, and wouldn't be shocked when you were charged $0.50 per text or whatever.
Apple has chucked that entire model out the window, and I think very soon texting ( as a separate service that you have to have a plan for or pay for )
Will be gone from the public's mind in about 3-4 more years.
Apple *shouldn't* lower its prices until it needs to... not to rip off consumers, but to have leverage when a worthy contender finally does come out, or the flexibility to lower prices when the inevitable iPhone 4G or iPhone Pro or whatever they're going to call it comes out.