There's a good article at Harry's Place on the death spiral that the Guardian is in. It's long, but it is worth a read.
At some point in the past, the staff at Fairfax started to consciously or unconsciously modeled their papers on the Guardian. They came to view the Grauniad as the epitome of what we (the readers) should have, and they've rather slavishly followed where the Grauniad has led. For instance, a quick search on the SMH site for "the guardian" returns over 10,000 hits. That's a lot of recycled Grauniad articles.
The parallels between the Grauniad and Fairfax are worth thinking about. It's interesting that in both cases, they've gone out of their way to offend what used to be a core group of readers, and now they are reaping the results.