If Apple creates the new IOS for you though and all you have to do is get your hands on it then the investment required just got smaller. Any reduction in the investment required for an exploit should be very carefully evaluated. Saying things like "This can't possibly be used by someone else." is either disingenuous or signifies that you don't adequately understand the issues, or you are lying to yourself. Whichever one of those that it is. It's in Apple's and frankly my best interest that someone highlight the truth of the situation.
[EDIT]: The below is more hyperbolic than I intended after a second reading. I'm leaving it since I already hit submit but I wanted to apologize for going there. :-(
This is like saying
Look... We'll create a nuclear bomb but it's okay we're
the only ones who will have it and nobody else is going
to be able to get one.
Maybe you can guarantee that no one else get's enough information from you to build one. However once you've built one the chance that someone could get the information from someone involved in your project to accelerate their creation of a nuclear bomb just increased by a non-trivial amount. And the potential risks are really high. Pretending otherwise would be foolish.