the reason might be the issues around position data integrity which most if not all GA installation do not provide which means that ADS-B reports have to be discarded by ADS-B in systems anyway.
Can you elaborate on why the data integrity is a problem?
Interesting though that ADS-B out will be mandatory in less than three years for certain aircraft (more than 5,7t or 250kts cruise speed) within europe but the certification standards are not yet published.
Those have mandatory Enhanced Mode S so radiating the stuff the whole time is a small step.