There is no single "silver bullet"for safety
While ADS-A, ADS-B, and ADS-C each have their useful roles, as well as pros and cons, clearly sir, you have either substantially overstated the role and worth of ADS-B, ...or perhaps still have limited knowledge of Air Traffic Service separation provision fundamental concepts and requirements. Many elements profoundly affect separation safety, ranging from basic flight planning information for strategic trajectory definition, to real time trajectory definition related to modern inertial systems, ILS, FMS, RNP, and GPS, ...to COM processes, to ATM tools of independent position fixing via radar and transponders, with backup airborne systems such as modern TCAS (which has specifically been responsible for countless saves and lives). So it is important to distinguish between fundamental ATS principles, operating concepts, and what was important to the past, and will be important to the future, while differentiating between primary methods, and backup methods for providing separation assurance. When viewed in that context, ADS is but one tool, but not the only tool, and certainly not the most important tool, for helping optimize the C-N-S triad, and ATM. In fact that FAA "ADS supremacy" fallacy and flaw is a root factor why FAA NextGen is heading directly toward a massive $40B failure at this point.