If someone's asking a complicated question, which only has long, complicated answers, which are already written up elsewhere, would you prefer that the question doesn't ever get an answer here, because no one wants to spend a lot of time rewriting something that's already out there on a more specialised site? Or that there's something descriptive and helping out by pointing someone to that helpful article?
From what I've seen, most of the answers that link offsite are either questions about one very specific app having a very obscure problem, or problems with people using obscure ROMs on obscure hardware and having obscure problems. We just don't have enough different people here regularly using enough different ROMs on enough different hardware, with enough different apps. There's hundreds of Android handsets, each of them has tens of different ROMs in various versions and there's hundreds of thousands of apps.
We would need an awful lot of people to cover obscure problems with all of that. Compare that to say, an iOS site that only has six possible hardware devices, a handful of OS versions (and almost no use at all of third party modified OSs).