Nobody reads the manual! Or do they?
I did read this, strangely, but like you I noticed that not even Apple follow it to the letter.
In our tests and reviews here we didn't see any problem in seeing a 1 or 2 second delay in the startup, because everything is ready to work on the third second in. It really didn't present the type of problem some of the other posters thought it would. A more complex load up would be painful, I think, as you would have the slight delay, and then another delay while it loaded the app. Any longer than 2 seconds is too far, I agree, even for our lightweight app.
We sat and went through all of the collective apps we have on our iPhones and found a few with a quick startup image. Most go straight into the initial window.
Unlike your average application on the Mac, which use startup panels, an app on the iPhone assumes a much simpler form, and the initial screen is largely ignored by the majority. Our third idea is to have an info button that shows a subview, which is likely to be the way we will go, I think