They will have to sell nearly 17M copies at $60 each to make a billion, unless there is downloadable pay content being sold as well.
Oh gee, you mean like reading Steve's biography? Here's an article that discusses it. It mentions that several executives petitioned him about calls out 2, but I've seen Forstall's name listed chiefly over the last several years whenever it's brought up. If you will recall, when the iPhone came out Steve said no to apps and that if people wanted apps they could design web apps. Eventually his viewpoint was changed and it's a good thing it was. Steve was not perfect or all-knowing.
Jobs is a reknowned control freak and the introduction of a new device will drive that part of his mentality to protect what he sees as the right kind of user experience out of the box. But notice that Isaacson siad he was initially resistant (follows his preferences) but allowed Schiller and Forstall to convince him, especially once they demonstrated that Apple would curate the apps and control delivery - remember, Jobs is all about the user experience and controls to that OCD. And the fact that he was supporting webapps indicates that he wasn't against apps on the iPhone, just not apps that had system access. Once his team could prove to him it could be done in a way acceptable to him it was a go, and Jobs enthusiastically supported them.
And at no point did I state or even imply that Jobs was perfect or all knowing. Understanding the personality of the individual helps to understand the thought process that produced the decisions that were made. As someone who is a generational peer of Jobs and moved in some of the same circles, I don't necessarily need his autobiography to understand how he thinks. Because ultimately what you do is proof of what you believe, and having watched Jobs work through his career, there is abundant evidence to indicate why he made the decisions he did.
I don't see any evidence that Jobs "caved" as you so blithely put it. He made informed decisions based on what his executives demonstrated was possible. It is not a rational assumption to state that Jobs didn't want apps on a platform that would clearly benefit from apps. Or perhaps you believe that Jobs just didn't get how important application were to the Mac platform as well? Your caved comment simply didn't make logical sense if you understand what drove Steve Jobs.