Disappointing they are delaying this change
But there's been a way to avoid this on iPhones for years. Settings/Privacy/Advertising/Reset Ad Identifier. Resetting the ID drops the relationship between the data they collecting on your in the past and the data they now collect on your new IDFA. So it screws Facebook and the others just as much, they just don't know it. I do it every couple weeks (basically whenever I read something about privacy on iPhones it makes me think "oh yeah I haven't reset the ad ID lately")
What Apple is doing (eventually) with iOS 14 is asking users if they want to allow a specific app to access the IDFA. Not sure what the point is, it should be an all or nothing thing. They should just default the IDFA to resetting daily and call it good, and play the world's tiniest violin while Facebook wails.