Why do people keep saying that ?
Because it's what Apple is aiming for in the long run. If the iPhone/iPad weren't the hottest devices in the solar system, maybe this wouldn't be happening. But let's face it, while Macs may be more profitable, iOS devices are outselling them by huge margins. What signal does this send Mr. Jobs? It tells him that portable/thin is even more where it's at than maybe even he imagined and they don't come much thinner!
iOS and OS X already share the kernel and Foundation, not to mention Quartz. That's about the only parts you can converge. The UI itself (Appkit vs UIKit) use completely different paradigms, so there's no real possible merge there, nor would you want or wish to.
And you haven't noticed a signal flare lately (cough...Lion...cough) that Apple intends to slowly change that Paradigm? iPad is getting more desktop features (e.g. print, dual-cores, more ram, larger more desktop-like programs, etc. and eventually more storage I'm sure). Meanwhile, Lion not only has the mid-Snow Leopard "App Store" that is awfully similar to the iOS App store (which hints at possible closed software 'some day', especially if most sales shift to the App store; that would signal Apple that people don't care about being able to buy open software and if it's not going to hurt their business, it sure as heck IS going to help it with a 30% take of software sales.
Meanwhile, Lion is taking even more steps to merge the GUI elements. Launchpad is just a start to get users used to a new way of loading/controlling their "App Store" software. And gee doesn't it look a bit like iOS methods? It will peacefully co-exist with the Dock (for now). Now look at the patents Apple has been filing for new monitors that tilt down so they can be used more like a tablet when needed and the multiple monitor output capability of Thunderbolt and it's not hard to see hybridization of the traditional desktop and the iOS touch interface that people seem to enjoy. Look at the trackpad changes Apple has been making over the past several years with gestures, multi-touch, etc. Notice how it's now a free option to get the magic trackpad instead of a mouse. I think you will eventually (when it's cheap enough) see a "iPod Touch" type trackpad that acts as both a magic trackpad and additional display device and dedicated launch pad device. This will combine iOS display + external monitor into one hybrid package for the new notebook and perhaps a larger 'iPad" sized display for "desktop" integration. In fact, you will probably be able to plug them in and use them as such on (then) older Macs to get the same functionality. Everyone has one anyway, so why not use them on the desktop?
The point is that while they are separate now, they are heading for integration. It will take time. ARM on the desktop isn't happening this year or next year. Maybe in 2013. They probably won't abandon Intel entirely until at least 2014. But you can bet if they can even get in the same relative 'solar system' as Intel, they will dump it. It will give them some separation from Windows again (it's just too easy to switch back right now; you only need to reboot to dump OSX) and it may make them more money in the long run and money, image and vision is what matters to Steve, not functionality or we'd have USB3, OpenGL4.x, SLI support, updated graphics drivers, etc. by now. They are clearly low on Apple's priority list.
ARM does nothing to converge things.
Nothing? I wouldn't go that far. Future apps will likely require only one compile to generate both desktop and mobile versions of the app. Once they merge the interfaces into their compiling tools, it'll likely be standard. On the plus side, it means you'll likely be able to play all those iOS games on your iMac and MBP (seeing the lack of games on OSX, this could help in that area). Given ARM will suck for full scale computer gaming, that's probably all you're going to get in the future anyway. Game developers avoid OSX, but are now supporting iOS so again, I give the Wii Versus Xbox360 analogy. Many games for Xbox360 aren't available for Wii (not enough power), but there are other games for Wii that are not available for Xbox360 either. The Mac hasn't seen a lot of that sort of thing in awhile. The market is too small to ignore a PC release, but you do see it with iOS due to the popularity of it.
I do agree that ARM is way too slow to replace Intel right now, but if Intel gets into the ARM game themselves, things could change quickly. They already have the technology to move quickly and their new 3D transistor technology is just itching for a new experiment in faster/lower power. They are already teaming up with Apple as it is, so I wouldn't write anything off. That 2005 PPC/Intel thread linked here is hilarious in how much is sounds
exactly like the "it can't be", "never happen", "it'll kill the Mac" talk in this thread. The only major difference is that ARM is slower whereas x86 was faster at the time. But we're probably talking about a 4-6 year time frame here. I'm sure Apple will keep their options open, however. I do think they are planning to merge the GUIs of iOS/OSX over time in a hybrid-like format as described based on their current plans through Lion.
