No GPS, no ADS-B. No ADS-B, no flying
Continuing the thread drift for a moment... this is both true and false. ADS-B gets its position from GPS (obviously), but that doesn't need to mean an IFR certified GPS. There are solutions on the market that give you complete ADS-B out for $2000. They include their own GPS. GPS is cheap - my nifty nixie-tube clock gets its time source from a $10 GPS dongle. It's IFR certification that's expensive.