Jim-


>You see, even though many cars are produced with defects, it is a fact that many more cars are produced that function perfectly properly for their users throughout their useful life.

You do realize that functioning "perfectly properly for their users throughout their useful life" is _not_ the same thing as being "bug-free?" It only means "bug not found." Or "bug not noticed."

Even if it is possible that code is bug-free, no code of any useful complexity can be proven to be so. And, of course you increase the cost of development past the point of benefit the closer you try to reach 100%.