If we make some conservative assumptions based on his actions and what we know of the man then it's safe to say he would allow the speech to become part of PBS documentaries but not used in corporate advertisements.
King's speeches are used in corporate ads. Did you watch the embedded videos?
Likeness rights, not copyrights, are what prevent the images of public figures from being used commercially in ways that imply endorsement. If I take a photo of the President (or any other famous person, in public or in private), I own the copyright for that photo. I can sell copies of it for a profit. But it can't be used in a way that implies endorsement. I need a model release for that.
I'm not a lawyer, but I believe it would be perfectly legally possible for the King estate to release all aspects of the speech into the public domain and still prohibit the use of King's image or voice in advertisements. Or it would have been.
I did see the videos, I know they are used in ads. I knew without watching any online videos as I've seen them on live TV. What I'm saying is that if he were alive today we could safely assume he wouldn't have allowed such advertisements to be made. Part of what I'm saying requires us to imagine what would have happened had Dr. King not died as it relates to copyright. He could have exercised the powers afforded to him by copyright to combat some of the uses of his speech the author talks about.
King's speeches are used in corporate ads. Did you watch the embedded videos?
Likeness rights, not copyrights, are what prevent the images of public figures from being used commercially in ways that imply endorsement. If I take a photo of the President (or any other famous person, in public or in private), I own the copyright for that photo. I can sell copies of it for a profit. But it can't be used in a way that implies endorsement. I need a model release for that.
I'm not a lawyer, but I believe it would be perfectly legally possible for the King estate to release all aspects of the speech into the public domain and still prohibit the use of King's image or voice in advertisements. Or it would have been.