Are you sarcastic? This sounds awfully certain. I see so many huuuuge holes in the argument.
1) Mars demonstrates exactly what one great filter for life is: exposure to space
2) Earth escaped this fate, for now, because our solar system seems to somehow have gotten a great dose of uranium long ago. We know our solar system has a far larger than average concentration of uranium, which is keeping the earth warm because the concentration of uranium nicely balances out the energy loss to space, and earth is of nearly the perfect size, in a near perfect position relative to our star, unlike Mars which is too small, to allow for life to continue for probably no more than ~6 billion years.
Why or even how did this uranium delivery happen? I mean probably it was a neutron star collision (but with what? Several options. Also the neutron star that did it should either still exist, or have left behind a black hole ... where is it? What happened to the thing it collided with? Truth is it can't be that far away, but we haven't even found that thing, so we can't actually even guess what the odds of this are. And before you say the equations predict it: cool, but those equations famously got all the higher element concentrations on earth wrong (famously there's too much gold) until we figured something out, and they still give a uranium concentration that's far lower than the Earth's. In that sense "science predicts" the earth would have become inhospitable to life 2-3 billion years ago because it would have solidified and lost its atmosphere a billion years or so after Mars did. Yes, we know uranium is preventing that but we don't know where the uranium comes from. So we don't know the odds.
3) Another assumption that fails: why would AI be the filter? Not nuclear weapons? Fusion bombs? Chemical weapons? Bioweapons? Viruses? Diseases? Other wars? Climate change? Environmental destruction? At one point I seem to remember reading an article that it was going to be a computer virus. There are so many other physical phenomena that can end life on earth. A nearby supernova (booms big enough don't have to be close to kill you), changes in earth's orbit around the sun, changes in other orbits, maybe even the Moon's, ecological collapse for other reasons, a new grey goo disaster, ...
4) humans exist NOT just because the earth is livable but because the earth got VERY close to killing all life through climate change (however, by cooling down, ie. the "snowball earth" extinctions). Those were not just extinctions and a dark silent end, they caused an explosion in biodiversity after a volcanic eruption ended the extinction in progress. We are the result of the explosion in biodiversity after the last extinction, in fact after every extinction event, and there's LOTS of them. And before snowball earth, it kind of looks like a "grey goo" disaster had in fact taken place on earth, it's just that climate change either destroyed enough grey goo or changed it's environment enough to end it. So earth created us, not just by allowing life, but by killing over 99.9% of all life at least 3 times and in fact a couple dozen times.
5) Another assumption. ARE there no aliens? How far out would we, really, have noticed them? 500 light years? Even that seems far, especially given that "the Silurian hypothesis" paper points out that if Dinosaurs had a civilization that didn't make it to the nuclear age, especially if it happened before the first dinosaur extinction (the one with the asteroid you're thinking of is the third and last), odds are surprisingly good we wouldn't have noticed aliens right under our feet. So let's very generously say 500 light years. How many planets in that range? 10 million or so. How many that aren't obviously excluded? (gas giant, cold worlds, too hot, too huge, too small). A couple dozen (ONE that we have actually detected). So reality is that if the odds of life are less than 1-10% (and that's an easy argument to defend) we probably wouldn't have seen life with current tech even "close by". Also life seems to require 5 billion years of processing before it starts making interesting signals so a planet that is very very very close to being good enough like Mars ... just wouldn't do it.
Yes there are studies, like the one from Aricebo, that claims we could detect some signals from as much as 12.000 light years away (still not even 0.01% of the milky way) but if I remember correctly such a detection requires a perfectly aimed signal and so it requires extreme luck to happen.
6) that shows yet another problem. Despite Elon Musk's bullshit, reality is that you will find on average a planet that can be (temporarily) terraformed (in tens to hundreds of thousands of years minimum, like Venus and maybe Mars) every 2-3 lightyears in our milky way neighborhood, which is presumably average ... why would you colonize them? You're not going to get resources from them, the distances are too large, energy required for that is too much. Plus once you climb out of a gravity well ... why would you ever dive into another one?
7) So the "no aliens" argument is purely based on aliens always doing the opposite of filtering: the assumption they would necessarily "conquer the galaxy" ... but would they?
Why? It seems to me leaving planets behind, figuring out fusion, finding the biggest hydrogen cloud less than 1000 lightyears from you, and moving into that would be a far better strategy (which is also the problem with Dyson spheres: WHY would you build that? You need the hydrogen, you do not need the star, yes with 1950s tech you'd need the star, but let's assume we can make the obvious advancements, shall we?
A bussard collector + a fusion reactor + a couple dozen lightyears from the nearest star at least seems far more comfortable than even earth, something like a large number of spaceships flying towards the great attractor (traveling on the cosmic web), outright exiting the milky way. To me, that seems the way to go.
And so your argument is flawed even on it's most basic premise: that a filter exists at all. The only thing the "great filter" needs to do is prevent a civilization from expanding more than a few hundred lightyears along it's orbit in the milky way and it would for sure have stopped us from finding them, even just in the milky way.