I agree that revolvers are not simple--lots of parts and pieces that have to work correctly every time. However, I've had failures with a revolver only twice (in 45 years of shooting them)--and both times were my fault. One time I left oil under the extractor and unburned powder flakes stuck to it, built up, and raised the extractor so high that the cylinder wouldn't revolve. Another time I reloaded some .38 Special and didn't seat the primers deeply enough. So, of course, they dragged on the recoil shield and the cylinder wouldn't revolve.
On the other hand, every semi-auto I've ever owned (and I've owned lots of them) has failed at least once. They were all maintained correctly and fed high-quality factory-loaded ammo.
And yes, I'm familiar with all the methods of racking or releasing a slide. However, at 80 years of age I don't have the grip strength I had "back in the day" and if the occasion arises that I have to rack the slide, I'm just not confident that I can do it.
And the idea of racking with the strong hand while holding with the weak hand really doesn't appeal to me. Not only is my weak hand significantly weaker than my strong hand, I don't shoot well with it either (yes, yes I know--one should practice shooting with both hands). And I really, really don't like the idea of having to switch the gun back to my strong hand from my weak hand. Not only do I lack grip strength, my manual dexterity is not what it used to be--I would hate to drop the gun in the middle of the switch-over!
Didn't realize you were that advanced in age - the M&P 380 EZ may be a better option than the 9 for you - lighter recoil spring (at least it felt lighter when I compared the two) and softer shooter than the 9x19. If you don't mind 1911 pattern pistols, Browning makes a real tilting barrel .380 1911 - its not a snappy little blow back - its a genuine scaled down 1911 that is easier to rack than a lot of other pistols.