That chart is fun, but it seems "Space Is Vast" and "Life Is Rare" are simple, logical, and rather obvious - and together they suffice to solve the Paradox.
I agree, and that's where I lean. I do not think we've been visited by intelligent life. Mainly because, you have to look at the probability that life gets started on another planet, which is not very high per planet -- so with billions of planets suitable to form life, only a few of them will (I do think life exists elsewhere though, just not on every suitable planet). Then there's the probability that that life will evolve into "intelligent" life. Then the probability that that life will not get wiped out by a natural disaster. Then the probability that that life will not wipe itself out. Then the the probability that they can discover interstellar travel (without emitting signals we can pick up on). Then the probability that they can discover us within the 100 years we've been emitting signals or so, our signals have not traveled very far yet. Then the probability that they made it here between the time they discovered us and now (small window). Then the probability that they did so undetected by any scientists observing the cosmos.