I didn't notice it, it just sorta happened; one day I became a pistol man. A lot has to do with the available alternatives. When I was younger, you didn't have much choice in carry autos. Now, there are not just a few, but a number of good choices that combine small size, shootability, and reliability in very reasonably priced packages.
All my life I swore by the j-frame revolver, but I've switch to the automatics over time for a number of reasons.
First, the ammunition. The 9MM is better then a 38spl and the 45 ACP is just about impossible to beat for self defense. Yes the 357 beats a 9MM, but I'm not one to load them up in a j-frame for daily carry. Yes, you can get a 9MM or 45ACP revolver, but my personal experience is that the 9MM suffer from some reliability problems, and the 45ACPs are fairly big guns. Got to give the autos the + here.
Second, the cleanup. If I carry a gun, I shoot it. I like to know it is reliable, and make sure it gets cleaned and the ammo rotated on a regular basis. The autos are hands down easier to clean. Got to give them the + here also.
Next, the reliability issue. I do agree it is tough to beat revolver reliability, but, I have never had an automatic that I could not get back into action by myself. I have, however, sent both my 640 and my 940 back to S&W for a problem I could not resolve myself. Most auto problems stem from lack of maintenance or bad ammo. These are problems that are easy to avoid. My experience with revolver problems are that, although rare (very very rare), they tend to be mechanical problems that take the gun out of action for good when they happen. All in all, I'd say that reliability is at best a push, but my personal opinion again is to give it to the auto.
Finally, capacity and reload. Yes, there are folks that can speed load a revolver faster then you can change a magazine, but I am not one of them. I agree that you probably don't need the extra rounds, and in fact rarely carry a spare magazine, but what can it hurt? I guess that I have to give it to the auto here again.
Does this mean that I feel bad about carrying a j-frame for defense - of course not. It just means that given the choice I'll go for the auto in almost every situation.