One of the better lessons I learned in Social Studies class in high school was that history swings back-and-forth like a pendulum. We go from one extreme to another.
We are in the era of BYOD and SaaS. We started with dumb terminals connected to mainframes, moved to standalone PCs, transitioned to client/server, got connected to the internet/web with browsers and now are connected globally to cloud-based servers and services.
There is a role for IT departments. What is certain is that the role of IT will shift to adapt to the times.