It’a an interesting debate, but I think you should differentiate between links given freely and those obtained in link exchanges.
Content may well be king now and/or in the future but Google needs an additional way to establish authority, else it would just serve up newly-created content-filled sites.
Inbound links are the easiest way to measure popularity and therefore authority but as we’ve discussed these are easily ‘gamed’ by indulging in link exchanges. In my opinion, Google will just find more sophisticated ways of determining if links are ‘free votes’ or have been manufactured via 2 and 3-way exchanges (it can’t be that hard for them to trace these – either manually or automatically) and start to lower their effectiveness.
Content is king because it’s what users want. And genuine, freely-given links to that content are a simple and effective way of separating the good from the bad. Links will always be important in my opinion, but exchanged links will become less so.