You’re exactly right. The book Rare Earth covers a lot of what you said. Also, if the earth was a little bigger, the gravity would be too high for us to reach orbit with any practical rocket. There could be intelligent life on super-earths without the means of reaching space.

Also, you alluded to this but it bears repeating. We have yet to find another star system that’s similar to our own in terms of having a similar star, a planet of similar size in the habitable zone and gas giants in the outer solar system. It’s quite probable that all of these things are necessary for complex life. Sometimes we’ll find star systems with one or two of these factors, but not all three.