Perhaps I'm missing something, but this seems to get the Fermi Paradox backwards. It explains why we haven't been visited by aliens (the light-cone of our radio transmissions is small and therefore aliens outside of it couldn't send probes to us), but the key observation of the Fermi Paradox is in the other direction; why can't _we_ see _other_ civilizations, in all of the billions of years of history in our light-cone?
If extra-terrestrial civilizations exist, we expect to be able to see some trace of them with our telescopes. Particularly at Kardashev type II and above (star-scale structures like Dyson Spheres).
> [The Fermi Paradox] explains why we haven't been visited by aliens (the light-cone of our radio transmissions is small
I usually hear the Fermi Paradox brought up in opposition to the reasonable-sounding null hypothesis of "life is common but stars are far." The argument goes that technological development and galactic colonization should be a very fast process (millions of years) compared to variation in nucleosynthesis/abiogenesis/evolution timelines (billions of years). In other words, if the story of the Milky Way were an hour long movie, the Milky Way would transition from empty of life to full of life inside a few seconds, and landing at the half-way point of that transition would be an unlikely feat of synchronization. That's why Fermi Paradox speculation often doesn't distinguish between "waiting for a radio transmission" and "already here" -- the transition should be very fast on geological timescales. Aliens wouldn't stick in "waiting..." for 100 million years, they'd eventually send colonists to grab the free real estate.
In other words, I don't think it's a mistake that the article repeatedly threw in the caveat "unless civilizations are extremely abundant" because that would be a common objection to its thesis.
> if you fix the Drake equation, the paradox dissolves
Yes, it's possible to toss enough uncertainty into the equation to raise the probability of low N significantly above 0, but the whole idea of FP is that you have to work curiously hard to make this happen.
If extra-terrestrial civilizations exist, we expect to be able to see some trace of them with our telescopes. Particularly at Kardashev type II and above (star-scale structures like Dyson Spheres).
Fortunately if you fix the Drake equation, the paradox dissolves: https://arxiv.org/abs/1806.02404.