Arguably it doesn't work in-universe, either, as proven by the fact that... well, it literally doesn't work, the dark forest is plenty bright by the time it all gets wrapped up.

From a western perspective the idea that the entire planet would successfully suppress a Dune-style disapora because "either we all make it or none of us does" also seems absurd, but it's not just a humanity prerequisite for the plot, it's a universal prerequisite for the dark forest, at least if the technology rollout is somewhat plausible.

Also, see above my point about Star Trek under the Prime Directive technically being a dark forest. Which is a funny meme, but also makes just as much sense as the TBP solution.

But hey, it's fun to think about for a minute and not that much wonkier than the Foundation or Dune takes on the same scale of problems. Except perhaps the slightly harder sci-fi approach making people take it more seriously than it deserves.