This is to warranty that user are running latest code/version, improvement like this will help the network and phone performance, not to mentioned security in general, just last year GSM key cracking was expose. Forcing user to run latest code it is just an obvious step towers security. And of course they are going to patch the jailbreaking holes, it is a hole after all that need to be fix, the only diference is that it wasn't found by Apple QA but by hacker community.
So why doesn't apple come up with a simple, secure way that allows a jailbreak should people desire it? They already said they're not going to fight it a while ago.
Besides, jailbreaking adds a lot of functionality and other nice things that the appstore simply does not.
If you don't know about it, SBSettings is a tool that, when the status bar is swiped, drops down and has a bunch of buttons customized by the user that can, for example, quickly turn on/off Bluetooth, Wifi, 3G, EDGE, Airplane mode, SSH, SMS alerts, show your data usage, and kill all background apps at once. Those are just some that I have but there are others.
There's an app called biteSMS that has so much more functionality over the stock messaging app provided by apple. Not to mention it provides a "quickSMS" feature that allows the user to reply to messages from any app quickly in portrait or landscape mode and the user can even reply from the lock screen without having to go into the phone itself. I have friends that have jailbroken their iphones and love the app, and I converted a friend to jailbreaking their phone just because they could do something like that.
There's an app for configuring the lockscreen to show your mail, sms, notifications, calendar ,weather, etc.
Jailbreaking also allows you to setup themes on your phone to give it a different look and also allows you to have different SMS tones than the few apple provides. Some people might say "so what?" but maybe, people like me just like having their phone look unique or have a certain feel to it that themes provide.
Hell I even put a GBA emulator on it to play pokemon. Call me 5 years old if you so desire but I had a lot of fun playing that whatever years ago in middle school and it's another option for a thing to do between classes hear at the university.
I could keep going for all of the different things it does but it's essentially the app store that Apple doesn't have. It's not to say that I don't like the AppStore, but Cydia just goes a bit further and I think having both is great. No, I don't market anything on the store itself I'm not a programmer or anything so don't think I'm trying to promote this to make money. I'm just an end-user that sees a tremendous amount of functionality achieved through jailbreaking and I think apple should take a step to put in some code into iOS that allows for jailbreaking.
I'm not saying they should provide the jailbreak itself and have Cydia come with iOS, but I think they shouldn't hinder the process rather make it easy for DevTeam to implement and then leave it up to the user whether or not they want use it.