Guest-blogging as a link gaining technique is dead.
Of course it's not.
Cutts seems to be under the mistaken impression that hyperlinks were invented to provide source data for his employer, and that if his employer now chooses not to pay attention to some of them then the rest of us won't either.
In reality, if there's a link in the guest blog post, people reading that post can follow it. If it's a popular blog and an interesting post on it by the guest author, probably quite a few readers readers will.
I know this is HN, but we're in some really pedantic territory here. Matt Cutts is simply saying that you should re-think your strategy if you want page rank and think guest blogging is a way to do accomplish that goal.
Matt knows his audience and doesn't have to spell out everything to the nth degree--when he talks link building it's 100% of the time page rank related.
The trouble is, there's something akin to Poe's law going on with Googlers these days: I find it very hard to tell whether they're speaking or writing specifically and assuming their audience will somehow infer their intended context, or whether they really are starting to believe that the entire Internet revolves around Google and they have some divine authority to tell everyone else how to make their sites.
When they start giving out blanket advice about what people "should" do, particularly when the advice is as self-serving and frankly laughable as it is in this case, I find it increasingly difficult to give them the benefit of the doubt. I suspect they damage their credibility a little more every time any of them speaks or writes this way.