The examples you quote are all technologies. What Marc is also predicting is a change in the technology of content distribution.

But what is not gonna go away are content producers. I still prefer watching movies made by Hollywood than home-made videos of cats. Where and how I watch movies may change but the fact that I will still watch professional made movies is not very likely to change.

Similarly newspapers may go away as a content distribution mechanism. But professional reporters and news agencies may not necessarily go away even with bloggers and social news sites and so on.