Science giveth, and science taketh away.
Kepler finds a ancient twin of the solar system, and gives us η = 0.1 [0], but (maybe) gamma-ray bursts sweep most galaxies clean of advanced life [1]. Also explaining the Fermi Paradox [2].
On the same /. page, no less.
[0] Which coincidentally is what we used to assume as a reasonable guess.
[1] as we know it, Jim. Extra-terrestrial life-wise, we’re in the business of looking for our keys under the streetlight. Because we have no way of knowing what any other sort of life would look like.
[2] Where is everyone?