The kind of control Apple seeks (to what purpose is irrelevant) is doomed to fail. You simple cannot control a device once it's in the possession of an 'adversary' (which in this context seems to be the owner of the device).
Once the attacker (again, the owner of the phone who wants to jailbreak) has possession of the phone, he has complete control over it. I wonder if Apple has this internal posture that they should make appearances of caring about jailbreaking (for the benefit of the carriers and their contracts) but actually it's not such a big deal.
You assume apple overly cares about jailbreaking. I feel they wish it were impossible, but knowing that it isn't, just want to make it difficult enough 'normal people' don't do it and start breaking things on the phone and not understand their jailbreaking is what broke things.
Hell, their AT&T contract was probably the only reason they got super up in arms about it anyhow.
The reason Apple closes the security loopholes is that they are security loopholes. It's not some sort of arms race. It's securing their platform.
Notice they have a pretty effective iBooks test for Jailbroken devices, but they don't deploy it widely, etc. I think they're at peace with the JB community as sort of a free research lab for them (hell, on device 3rd party apps came from the JB community first!) and use them to fix security holes in their platform as they are revealed.
Well, it's not that effective; it was worked around within days of showing up. Interestingly, to my knowledge, Google's similar check to prevent rooted devices playing movie rentals hasn't been worked around yet.
Comex and others are finding bugs, and Apple are fixing them. Not because Apple are irrational control freaks, but because the bugs they find and use to jailbreak the devices are extremely serious security holes. To not fix them would be incredibly irresponsible.
Actually, not really. From what I know, the keychain security hasn't been broken, except through brute forcing the passcode. While that's usually possible for the standard 4-digit passcode, it's not always possible. Jailbreaking is a necessary step to get the access necessary to brute force, but it doesn't magically break open the device for full access. (However, I am not an expert at this. I've talked with NerveGas (http://www.iosresearch.org/), but he's the person who really knows the most about that kind of stuff.)
A lot of what people are trying to protect is stores in the clear, though: I personally don't want people piking up my phone and stealing my address book and photos. Google's approach to this, a supported "jailbreak" (fastboot oem unlock) that formats the phone as it does its job, is tome the best solution, as it guts the incentives of people like comex to weaponize an exploit so well that any evil idiot can use it (in essence, the only people with the technology would be the "larger evil", as opposed to people like your nephew, ex-husband, or business rival).
They transparently do. Which makes total sense; the diminishing returns on jailbreak prevention are steep. Once you've made it enough of a hassle that 95% of your user base is confined to your ecosystem, how much is it really worth to you to get that last 5%, who would probably just switch to Android anyway?
I'm pretty sure that's correct. I know they take stuff like JailbreakMe seriously — remote code execution exploits and sandbox evasions might cause real issues — but I don't think they care all that much about your normal USB-based jailbreak.
The other replies seem to ignore the fact you are presenting, they don't give you administrator access to a device they sell you, but retain it only for themselves. You're right in saying that this is just in general an untenable situation given just the general problem is as you say, the potential attacker and potential customer are potentially the same person.
Once the attacker (again, the owner of the phone who wants to jailbreak) has possession of the phone, he has complete control over it. I wonder if Apple has this internal posture that they should make appearances of caring about jailbreaking (for the benefit of the carriers and their contracts) but actually it's not such a big deal.