All objective experience over the past seven years has shown that every successful effort to reduce robocalling has been the result of an enforcement action or fear of an enforcement action.
Beginning in July 2021, car warranty robocalls declined 95% after the FTC opened an investigation into several telemarketing businesses. The FCC also issued notices to telecom carriers in July 2022 to disconnect a different group of businesses that had been sending car warranty robocalls.
Source: FTC.gov