There is an all-in-one article including every part from this series (if you want prefer to read it all at once instead of "by installments")
This is more a misconception among executives and people who make decisions about buying these types of solutions. The consensus in the Accessibility community is almost unanimous: overlays don't work. None of them fully work.
As we mentioned in a previous section, there is no one-size-fits-all solution for Web Accessibility. And that's exactly what overlays try to be.
Things may change. While accessibility overlays may not be enough to ensure Web Accessibility at the moment, with the advances in AI and machine learning, they might become an alternative in the future. But currently, they aren't a solution.