Again, in a broad swath, the kinds of people who chose to go to digital agencies are the ones who embrace change and are used to continually altering course. I still see PR firms whining about why they “deserve” to own social media, rather than getting in the trenches and leading.

You mentioned that PR firms try to own digital execution but that they have been lagging behind in the adoption of digital tools. I think this is accurate, to a degree. Most PR firms are still essentially vanity marketers who are pushing a simplified message to get their clients SOV in a target media (ie they’re the people you pay when you want to see your face in print). Most PR firms aren’t passionate about media because they only touch a small slice of it so your criticism is largely valid.

Where I disagree is that digital agencies are somehow better equipped to own digital engagement as it stands today. While digital agencies have been somewhat quick to adopt some of the tools, they are still generally more focused on building interactions than building engagement. PR firms, on the other hand, have traditionally been the agencies that brands have chosen to broker their most important relationships and a case could be made that online relationships are an extension of that. Digital agencies have generally failed at dealing with user engagement that falls outside of their predicted UX flow.

It remains to be seen whether or not PR, or any other segment of the marketing food chain, will make any progress climbing up a notch or two as Web marketing becomes more personal and conversational. PR agencies have failed at seizing these opportunities in the past and will probably lose out to larger (and better funded) ad agencies and interactive shops once those guys see the importance of moving beyond the “declare” and “demonstrate” aspects of their business.