That's a bit surprising to me. I haven't noticed this (not much of an app person), do many apps use the recommended technique? Personally I would find a splash screen that looks like the first screen to be confusing.
Plenty do. The idea with that guideline is that it resembles the first screen the user sees, but in a "vague" manner - that is, maybe it just has the title bar and empty table view with no data filled in.
The idea is to give the user the impression the app has already started instantaneously, and you're just waiting for data to roll in to populate the UI.
Yeah, I'm using it in the project I've got in development right now -- actually sort of a hybrid approach. It's a grayed-out version of the main UI, with a "Loading..." message overlaid. I think that's a pretty common approach (graying it out, with or without an explicit message).
The app needs to load something close to 200 fonts (it's a design-oriented app). If they're not all present, the font choice list won't render properly. Lazy-loading isn't really an option -- otherwise the user will be sitting there watching the UI slooowwwlly render each font choice, one by one, while he waits to do something with them. Better to take the hit at startup, IMO, rather than making the user pause while he's in the middle of creating something.
All Apple apps (inbuilt or downloadable) follow this guideline. Amongst the non-Apple apps that follow it are Reeder, WhatsApp, Twitter, Sykpe (sort of), AIM, Shazaam, Instapaper and so on.
