It was probably already covered by someone - but IMO I think revolvers will never die off, and remain great for carry for the same reason I keep a revolver as the bedstand gun.
I don't know of any semiauto where - in the (albeit highly unlikely) event that you get a dud/misfire - you can simply pull the trigger for another try. I guess to me that's worth alot.
Not that it isn't hard to rack the slide for another try, but in a high stress, low time limit scenario - I'm likely to be running largely on automatic -and I want to keep what precious little of my brain I actually use - dedicated to the task at hand.
And - I would consider the conditions where I have to draw to be a rather high stress event....