You can set the IDFA on iOS to all 0's in Settings. See: https://support.apple.com/en-us/HT205223 under "Opt Out of Targeted Advertising" (at the end).
It's what is happening with Safari (and the other browsers). First, knowledgeable users are empowered to make a decision, then, that decision is rolled out automatically to the masses. E.g., https.