From a technical standpoint, revolvers have been obsolete for over a hundred years.
I think folks would have disagreed with that 1912. In fact, they would have disagreed in 1942 or 1972. Many of us disagree in 2012.
The official definition of "obsolete" is "no longer in use or no longer useful." I don't think we can say either of those things about revolvers.
An acquaintance who went from not owning one a couple of months ago to shooting one exclusively in IDPA would also disagree.