> Even if we did have a better idea about this probability, we still couldn't rule out that intelligent life had by chance formed relatively nearby, relatively long ago, thereby allowing them to reach us by now.
What is "now"? Within the next 100,000 years? In human terms, that's an eternity, and in galaxy term, that's an insignificant amount of time. In other words, almost certain not to happen. Even if it does, do we even notice? Chances are they either immediately kill us all, or they just observe and will stay hidden. A face to face interaction is scifi, not reality.
Tbh, on the list of things that humankind should worry about, an alien visit isn't even in the top 100.
It's understandable that it's a great topic to muse about, especially among tech folks. It's been part of scifi lore for generations and one can spend a lot of time discussing technical aspects. That's by far less messy and depressing than dealing with actual real-world problems (like wars, drift to dictatorships, oppression of minorities, inequality, climate crisis, human-made ecological disasters, heritary or contagious diseases, etc etc). Though when it's about devoting actual societal resources, it would be a waste to spend them on alien visitor questions beyond writing novels and making movies. Even if it's more fun to nerd out on intergalactical travel rather than preventing school shootings.