Failure to fire seems to be one of the more common problems with the PPK. I would think S&W would have designed that problem away, but I guess not. If S&W knows what the cause of light firing pin strikes is due to having to fix a lot of them, why not a fix in the design of the gun.
I suspect S&W and most other firearms manufacturers choose to hold cost down by doing as little quality control and inspection as possible, trusting the high tech machining to hold parts within specification. Nothing is perfect and poor to bad quality parts in guns that go out the door to customers are the result. I believe the firearms manufacturers think a customer that receives a gun that just plain doesn't work or has problems, like most, will get rid of the piece rather than have the manufacturer fix it. I also believe that way of thinking causes that unhappy customer to never buy from that manfacturer again.
Being human, we tend speak out on the forums when we have a gun the has problems. I suspect persons that are happy with their gun seldom post positive comments on the forums because a gun that is free of any problems is what we all expect and that doesn't need to be talked about.
There has to be a lot more happy persons with their firearms purchases than there are unhappy, otherwise the manufacturers would go out of business.