We're on a forum populated by us revolver loving luddites, so keep that in mind and expect that to color a lot of the responses.
No, I don't think the revolver is still relevant. For awhile they held on with ultra small carry revolvers (J frames, LCR, etc) and big revolvers for big game, and those still have their advantages, but even they are getting supplanted by small autos like the LCP, G43, an P365, or more powerful autos like the Glock 20 by more and more users.
The full size service revolver has not been relevant for some time. If we're playing the statistics game, none of us are ever going to get into a gunfight in the civilian world, so we may as well just not carry a gun at all, but since we're clearly not going down that road, we may as well use the best tools for the job.
For less than the weight and less than the size (and less than the price...) of a 2.5" Model 19/66 I can use my P365XL and have twice the capacity, faster reloads, better reliability (this gets debated to death, I've had many more issues with revolver reliability than I have with modern autos, and the revolver failures have all been show stoppers until you can get back to the workbench), and similar or better ballistics due to the barrel lengths.
Will a revolver still kill someone dead? Damn right it will. Is it the best defensive tool? Absolutely not. They're still neat and I still love em but we can all do that without ignoring progress in the defensive gun space.