You've made three true statements, but I don't agree if you're implying that they prove that "nothing has changed". Bugs still appear, but they are significantly less common (per project or line not per year) and not as damaging when they occur. This is a non-trivial change for the better in the realm of C application quality.

There are more slaves in the world now than ever before in history, but global society has still made great progress on eliminating it in the last thousand years.