That's an interesting article.
Whenever I read something about the Fermi Paradox, I always have the same thought.
I imagine walking through a park and taking a few turns off the beaten path. I reach an area that seems pristine, watch the may flys buzz in the sun light, then go home at dusk.
3 years later, thinking fondly of my secret area of solitude, I return to find it is untouched, may flys still buzzing in the sun light.
From the perspective of the may flys, who only live for a day, it's been over 1000 generations since the lumbering giant gazed upon them, leaving the gift of the apple core which generations feasted and grew fat on.
Or they didn't notice me at all, walking past they mistook me for an odd tree and made no note of me in their history.
Fermi assumes too much, that aliens exist on our time scale, that we would recognize them when we see them, that they haven't been to earth but obscured in ancient stories. It bothers me as a lack of imagination.