I think it's kind of unfair for Apple to lock us out of our own devices. It's ours... we paid for them... we should be able to do whatever to them as long as it doesn't break the law. If they would have just opened the platform up for us in the beginning, there'd be no such thing as jailbreaking. I think of the iPod touch as a tiny computer running OS X. On a desktop computer, we can see all the files and we have access to nearly everything OS X can do but, the iPod touch is being closed up tight? People run 3rd party Apps on their Macs all the time and the Apple warranty doesn't have to cover damage caused by them... only the makers of the software. Why isn't this the same on the iPod touch/iPhone?
If they'd opened the platform in the beginning, there would be room for all kinds of malware and harmful hacks. Apple makes consumer electronics products with the intent of making it
easy on people to use their product. They shoot for the whole "It just works" ideal.
Also, the iPod touch is heavily a port of the iPhone. The iPhone isn't just Apple's baby, but AT&T also has a huge stake in it, so it's very risky to let people install what they want willy-nilly. It isn't just a phone, it's a smart phone connected to the internet. So it is just as susceptible to worms, viruses, trojans, and hacking as a computer. As an always-on internet device (in the case of the iPhone), it would be potentially very harmful to AT&T if such a problem arose.
I have a feeling that this is why the SDK has taken so long in coming: Apple wasn't sure if it was necessary, and AT&T probably didn't want it at first. But after hacking started happening, the two companies needed a secure channel through which they could provide applications. This is where the SDK and iTunes enter the picture.
Buying apps from iTunes also allows people to purchase applications like they do music: safely, reliably, and securely. It only makes sense that iTunes would be the way, and I'm sure Apple will screen the apps that make it into the store for bugs and malware. (It will be interesting to see how rigorous and restrictive they are, but I'll give them the benefit of the doubt for now.) This way people don't have to worry about downloading from various sources on the internet and potentially screwing their iPods/iPhones. If it's in iTunes, it's safe, end of story, just like with movies or music (no risk of viruses, unlike torrents or illegal download sites).
And I suppose that one could fault Apple for so obviously porting their iPhone stuff to the iPod touch, but the touch was meant to be an "iPhone for the rest of us" who didn't want the phone part...just the cool touch screen iPod. So for ease of development, it's in Apple's best interest to keep the firmware virtually identical.
My two cents. Now go ahead, blast me for being an Apple sycophant.
(For the record, I have a jailbroken touch, but this is my choice and my risk. And I feel that it's Apple's responsibility to fix all the little holes exploited by jailbreakers: unsuspecting people could easily stumble upon a site that would steal their internet info without their knowledge by executing code similar to a jailbreak, but harmful.)
