It's unsafe for aviation to be entirely dependent on GPS and self-reporting systems like ADS-B. Planes should still have VORs available, even though they take up a lot of acreage next to airports, the ground should still have primary radar, and aircraft should still have their dumb old AM VHF radios.

Large aircraft typically have at least three completely different navigational sources - VOR/DME, GPS, and inertial guidance. Over- reliance on GPS is dangerous.