I don't understand why you reach this conclusion. Every design decision made for Mac OS X has to be architecture agnostic. The OS X Kernel runs on ARM. Apple can compile cocoa apps for ARM. I think it is extremely likely they could provide tools for exisiting Macintosh developers to recompile their apps to run on ARM architecture. The problems would be:
[1] Losing bootcamp support. Apple could soften the blow by provining support for iOS apps instead.
[2] It is unlikely Apple would be able to provide virtualisation (ala Rosetta) for applications which hadn't been recompiled for ARM.
[3] Developers who don't use Xcode. I'm not sure there are many left. I can think of one quite big one though.
[4] Having to support the Mac on two different platforms. Which may or may not be that much of a big deal.
I definitely agree that Apple has every intention to make the switch as soon as they can to get away from the evil empire known as Intel. Intel literally set its own demise in motion when it went well beyond acceptable by kicking out Nvidia over technicalities.
I also think there are more problems than you have listed... and that's just the start of it. However, in the long run, I believe Apple can successfully transition due to the love of iOS products. With iOS encouraging users to buy Apple products, they will consider buying Macs too.
I believe OS X has no innovation in its latest offering. I have to believe that Apple is planning a huge upgrade to OS X 10.7. However, the poster before you thinks 10.7 will be the ARM switch. I don't believe we're anywhere near that close to a switchover. Quite honestly, the technology isn't there yet. Apple will need a clear advantage in both performance and power efficiency to make the switch.
Apple's user base is so strong and small enough that it can endure a switch. It's not like Microsoft with a billion users worldwide. People that love Apple products will put up with the hassles of none of their current apps working, whereas Microsoft doesn't have such an advantage. And that's really just the start of it.
Does Apple even want to sell Macs anymore? I know their Macs have become less than 1/2 their revenue. In the last year, it has become obvious that OS X and Mac computers were not a focus in any way, shape, or form. The lack of innovation to Mac computers is a huge problem with the fan base. If Apple does want to take its computing business to the next level, it's going to need to drop its attitude and rediscover its passion for the Mac.
I do believe it's correct for Apple to focus on the iOS products right now while they can gain a foothold in both the smartphone and tablet markets. However, Apple has the resources to focus on both iOS products and Macs, but it has failed to do so. The current Mac offering is horrific. There was zero innovation in the latest MBPs. The wait between updates was longer than ever before, and they brought NOTHING to the end users. Apple needs to use iOS to build its Mac brand not forget about its Macs forever and just focus on iOS products.
We will see where Apple goes, but I hope that Apple sees the Mac as a bigger opportunity in the long run than the iOS products. Apple failed in the infant stages of the computing market with Macs, and it's obvious it will not make the same mistakes with iOS products. However, in the long run, I believe the Mac could own domination of the computing markets, and it just might be the iOS products that help Apple do that. With lower cost ARM SoCs, Apple can have true 12-hour battery life, faster Macs, and systems that blow us away.
But, it has to REALLY WANT IT BAD... does Apple want the computing business anymore? Us computer users are a pain in the ass. We want it all now. iOS product buyers are amazed by what's free (the simple user interface and apps designed by developers willing to give them away). And there are subsidies to sell cell phones for $400 less giving the user more affordable access. Maybe a Verizon line of 4G/LTE cards in every new Mac would help with that?
I do say ARM is the future, but I believe it's further away than we might guess. I don't believe it's something Apple will be willing to consider until the advantages far exceed the disadvantages. Right now, it's focused on iOS products. If we give them five years, the iOS dominance may allow it to focus on its Macs and switch with its next OS... meaning beyond OS X. I don't believe OS X 10.7 will be an ARM switchover.
We should all hope for Intel CPUs in our next MBAs but only if they're paired with ATI/AMD GPUs. If Apple cannot get both in there, we're much better off with an AMD CPU/chipset/GPU combination. I wouldn't plan on the next MBAs having ARM SoC designs... and no Apple isn't going to deal with porting everything for one Mac that doesn't even sell well.
