It's all about the experience
Apple's problem with the iPhone is that they treat it like one of their Macs - a fixed spec with authorised upgrades.
Apple don't want iPhone users to have the sort of freedom that regular Bluetooth support provides. Some might argue that the userbase is better off for it, and I'm sure plenty of apologists will point out that Bluetooth is "insecure", or some other contrived excuse to explain away the unjustifiable crippling.
"Users can't brick their phones if they don't have filesystem access". True, but when has filesystem access ever allowed a user to brick their phones? Files marked as "system" is nothing new, I have full access to the "C" drive on my Nokia N95 - and try as I might I can't do anything that would irreparably damage it. The worst I could do in fact would be to wipe or otherwise corrupt the system settings and end up returning the phone to factory spec.
On the flip side of course if you stop users from being able to do things like this at all then it means less support queries. Again, is Nokia inundated with people who keep factory resetting their phones over and over? I doubt it. Therein lies the rub - Apple treats its users like children who simply cannot be given the keys to the kingdom lest they inevitably end up bricking their hardware. This is a false economy though - security through obscurity - a secure device should stand up to full access to the filesystem and implement appropriate safeguards to stop people from doing bad things inadvertently. Nokia manage it, as do Symbian, Microsoft (Windows Mobile) et al - so why can't Apple?
The scary part about things like this is how people rationalise their freedom being taken away so easily, "Apple knows whats best" is a common attitude it seems. That notion scares me. Whilst I can appreciate companies denying access for the good of the user, or to protect trademarks, or whatever, but denying access just because it doesn't fit in with a business model - and for no other justifiable reason - is not good. The irony of course is that often the same people who talk about DRM taking away peoples freedom to do what they choose with things they've legitimately bought wlil defend Apple to the death seemingly only because Apple has a "feel good" aura about it.
Apple is in my mind at least just as crafty and conniving as any of the "usual suspects" like Micro$oft (lol), Sony, RIAA, MPAA et al - the only difference is the Apple PR machine and the legion of cultists have managed to achieve what the others can only dream of: imposing draconian restrictions on their customer base and leaving them smiling.
(I own a MacBook Pro and - soon - an iPhone, before anyone chimes in about anti-Apple attitude. The difference is I see the devices (and Apple) for what they are rather than as life-changing products)