You've seen the button. It floats in the corner of websites — a stylized stick figure or a wheelchair icon, sometimes pulsing slightly to attract attention. Click it and a panel pops up offering "accessibility profiles" — increase contrast, larger fonts, dyslexia mode, screen reader mode, content adjustments. These are accessibility overlay widgets. accessiBe, UserWay, AudioEye, EqualWeb, and a handful of smaller vendors all sell variations of the same thing: a JavaScript file you add to your site that promises automatic ADA / WCAG compliance. They don't work, and the regulators have noticed. What an overlay actually does The honest version is mechanical: an overlay loads in your visitor's browser, scans your DOM at runtime, and tries to patch missing accessibility attributes — adding aria-label here, adjusting role there, sometimes injecting a parallel UI for screen readers. The implementation is impressive on demos. The reality on shipped sites is that: Overlays can't fix what's structurally broken.…