We're all different.
Your trust in fate philosophy might be a slightly more understandable approach if places were inspected frequently and a bad place was picked up and closed down quickly. But the fact that they are not doesn't make your approach a sensible approach. In most places it is infrequent. So your optimism in inspections doesn't take account of the extended periods before and in between an inspection. At least inspections tell,you what they were like last time they were inspected and after a few years in an area a pattern emerges. It tells you as much about which owners and operators are not just OK when inspected but also which ones you can trust over time. Many with poor ratings also always seem to be changing hands often.
You also take a rather fanciful view of how this is done. As I posted above a 0 and 1 rating is urgent action necessary. If you are happy eating in that place in preference to a clean place - and that clearly sounds rational to you, but may not be to many other sensible people.
Most places with a 4 are desperate for a 5, and those with a 5 do not want the shame of losing it. It is a matter of pride and reputation. I've seen many Asian places where our second home is that have never risen above base levels and people talk about them and avoid them for those that proudly display their 5 ratings. The apps also now tell you rated places that are close to you.
I can see both sides of this, and I pretty much agree with Emma, but it doesn't seem to me as though you're factoring in the taste of the food in a given restaurant. If the food simply tastes much better at the C or D joint next door to the A joint, I'm going for taste. Only if they were equal would I consider the grade.