I came to the same conclusion: that DA should be applied only to the people who knows about DA. And it makes it worse. There are two ways how to apply it DA-people. Using years and using number of people (rank) who know about DA. The second way is even worse as the number of people is growing exponentially, and so we are near the end of the group of people who knows about DA.

It may not mean extinction, but strong and universally accepted DA rebuttal, or drastic fail of the number of people.

Global catastrophe in next 10-50 years unfortunately seems to be most likely explanation.

(The ideas were also known to Carter in 1983 when he presented anthropic principle and already knew about DA. At this time he was the only person on Earth who knew about DA and he understood its implication for small class of people who knows about DA and it really made him worry about extinction soon. I forget where I read about it.)