Half of the engineers I (want to) talk to refuse to switch from IRC, and the other half refuse to use it. In the end, I use both, and so do lots of other people.

Should we expect ordinary, non-technical users to behave substantially different? It's not clear to me that we should; most people find the status quo "good enough," and the activation energy for switching is higher than the minor inconvenience of some of your social circle having a slightly worse user experience.