I don't agree with any of this.
Apple have never been afraid of canalising themselves, the iPod to the iPhone, the iPod Nano, the iPad mini, the 11" Macbook air...
You should read Isaac Walter's book on Steve Jobs, and how Apple have never minded cannibalising their own products.
They don't add a file system or mouse support to the iPad because it is a different device that does different things.
Adding a file system and a mouse wouldn't make it a real Post PC device, it would just make it a PC.
The moment Apple adds a file system to the iPad it will die.
It's great that you've jail broken your iPad, added a mouse and it's working for you and how you work, that’s great. But you are a rare case.
Pretty soon, maybe even 2013, Apple will sell more iPads than Laptops anyway, so your argument isn't valid. Tablets will destroy the laptop industry, they already are, ask Dell and Sony.
adding a file system and cursor support would not make the iPad a PC, it would make it a more functional tablet. how would the iPad die if it has a file system? according to you logic, Android tablets would have already died off but last time i checked their market share is growing.
there is cannibalization within product family and then there is cannibalization across product family. it's the latter that apple is trying to avoid.
i may be a rare case b/c i have actually taken the steps to jailbreak the iPad, but it is not rare for iPad users to desire cursor input. i see it all of the time - people trying awkwardly to use their iPads as laptops. while the iPad was not designed to be a laptop replacement, consumers are trying to make it one since the benefits of an iPad over a regular laptop are numerous - battery life, size, weight, instant-on, excellent cloud-syncing, and the fact you don't have to deal with a full blown OS. adding a file system in iOS would not crush performance, it would not introduce glitches, it would not "kill" the iPad experience. in fact jailbreaking my iPad has done NONE of these things and has made my iPad even more functional and even more useful
regarding the sales numbers of iPads vs Laptops - your comment actually supports my argument. as more and more people ditch their laptops and move to tablets, they realize how many shortcomings the iPad has over their regular laptop which they are attempting to replace. they will start to demand certain features ported over to make the transition easier. cursor support being one of them, and some sort of native file system. it happened with Android, and eventually it will happen with iOS when Apple has figured out a way to protect profits.
you act like cursor support and a file system would be destructive to the iPad. you realize cursor support (just like adding a bluetooth accessory) is an optional feature that doesn't have to be utilized by the user. if you think throwing in the ability for optional cursor support is a stupid idea, then you must feel the same way about a BT wireless keyboard. however, that's a rather popular accessory and sells very well (Logitech Ultrathin, Kensington KeyFolio, and ZaggFolio). with a few lines of code, apple could allow cursor support then it would be up to you whether you want to use it or not. would you rather have that freedom or would you prefer if apple continues to dictate to you how they want you to use their product and prevent you from using it in any other creative way.
steve jobs, during one of his many discussions on the development of the iPad, said that reaching across a keyboard to touch a screen is an awkward movement. so going with a tablet solves that problem since the user can hold the entire experience in their hands. well guess what, having an optional mouse or trackpad built into a case also solves that problem and allows the user to keep the iPad on the desk.
don't get me wrong, the iPad is the best tablet there is. that's why i bought it. but i'm keen enough to recognize that it could be better and i don't just settle for what apple dictates. you might ask why i didn't buy an Android tablet then, well the reason is that apple makes a better tablet with a better experience. jailbreaking the iPad allows me to borrow features that i desire and implement them on the better more competitive device