The first "P" in PPP is an indication that the PPP is a lifelong quest, more so than something one buys off the shelf. Even with a good packin' pistol in one's possession, there is always the possibility that a different sight set-up, or custom grips, could enhance the whole package.
Moreover, advancing age changes things. My formerly strong right hand, for example, has become skinnier and bonier, so what once pointed well for me may no longer do so. I used to like black sights, but that is not the best for my eyes anymore, so I am researching gold beads, gold blocks, colored engraved lines, and even fiber optics, though I find the latter distasteful. (Yes, I am a lefty, but pack my primary on my right hip. Long story!)
It helps to have more than one near-perfect packin' pistol, so that there is something to carry while another pistol is away at a gunsmith.
OK, I will stop rambling now.