While optics do fail (ask me how I know after reviewing photo below), so do iron sights. I’ve had the front sight come off a Dan Wesson Guardian and one on a Glock 43 come loose, both while in use. I still trust both. I’ve had guns occasionally not function properly, sometimes magazines, sometimes ammo sensitive, sometimes operator error. I still trust the guns once I figure out failure point.
Personally, I have optics on all my carry guns except a G43 (because I don’t want to pay to get slide milled). Every one is a Holosun SCS (Solar). Every one is easily charged with a solar watch charging light without removing optic from gun.
In the exceptionally rare chance I need to employ one of those SD guns, I’ll take the odds that the exceptionally rare occasion an optic fails will NOT be at that exact same moment in time.
To the post concerning zero, when that G43 front sight came loose, it certainly lost “zero”. Even then my hits were on the silhouette at 10 yds. They would hit closer I’m sure. I wouldn’t be using a pistol for SD much past 10 yds (30 feet) as I’m not active LEO. Losing zero on an optic is most likely 1-2 inches in a direction…still take the odds the rounds would still land on the threat. If you shoot your SD guns often enough, you’ll know. I’ve yet to have an optic lose zero or come loose. I torque to manufacture specs and sparingly use blue loctite, even though some manufacturers state not to use it.
I’m sure there were times in history where folks were told never trust that new fangled pistol, it’s not a reliable revolver; no pistol without a hammer is reliable; any barrel under 4.5 inches isn’t reliable for self defense; unless you’re using .45 ammo for SD, you’ll never stop a threat, etc. (I’m sure some still believe those and that’s their prerogative).
Personally, I trust optics implicitly and believe that they are through their growing pains. Now they continue to make them better.
But, this can happen…stock G32 shooting .357 Sig, which gun designed for. Manufacturer replaced under warranty. I replaced with a Holosun SCS-MOS and never looked back (or had another issue).