Out of what, 500-1000 billions of planets just in milky way? I dont think folks do realize how big those numbers are. And there is no reason to ignore rest of the universe if we talk about probabilities and statistics
It's just another fraction to multiply in the drake equation. Start with planets, cut down to rocky ones, only in habitable zone, only rotating a certain way, only with plate techtonics, etc etc.
Or using your numbers,
1/4 factor eliminates 750 million possible candidates. That's not a happy thought.
