Consider the number of billion to one coincidences that have got the Earth and us to where we are.
The planet is at exactly the right distance from the right kind of star.
Early in the planets existence we gained a very large satellite.
This has given us a tilted, stable rotation.
Thus there is liquid water. There are seasons. There are marginal conditions because we have tides and weather. This has not only allowed life to start, but the changing marginal conditions have allowed and encouraged evolution.
Along the way, there have been various planetary catastrophes that have rearranged evolution by changing conditions radically.
Humans, as such, have only been around for the last million or so years out of the two and a half or so billion since lifeforms existed. We have had radio communication for just over 100 of those several million years.
So, if you figure that a radio signal takes about 100,000 years to cross just our galaxy, and if someone over there notices it and replies by return, it would be between 50 and 200,000 years before the reply turned up, depending on distance, so the chances of anybody noticing anybody else are slender, bearing in mind that we don't know how long we can keep our present technological age going. If chance has allowed another planet with life forms capable of compatible technology to exist, what are the chances of ours and theirs existing in a matching time frame that would allow any form of actual communication?
There is a bit of popular almost mythology being created about Earth and 'special' circumstances leading to life here.
For example the habitable zone from the sun and the moon stabilising the axis rotation to give us seasons.
The sun is now approximately half way through its lifetime. As a star ages, it get brighter, increases in size and puts out more heat. The earth probably wasnt always in the 'habitable zone' which has been moving outward since the sun first started to burn off its fuel. The habitable zone will in approximately 1 billion years be outside the earth's orbit and be between earth and mars. Eventually the sun will grow in size such that it will probably expand to the earth's orbit pushing the habitable zone further out. It may somewhere up to this time, push it out to start to thaw Titan from its frigid temperature and make life habitable there.
The sun will continue to 'live' for another 4 billion years after that before collapsing to a white dwarf.
So, it isnt 'just by chance' that earth is in the habitable zone. Complex life evolved here because the earth has been in the
moving habitable zone for some time.
The most widely accepted theory for the formation of the moon is a collision with another proto planet about the size of mars. Not only did this create the moon, it also introduced the axal tilt of the earth we have today and also started or increased the earth's rotational speed about its axis.
If a proto planet had not slammed into the young earth and no resultant moon formed, it does not mean complex life wouldnt have evolved here.
The earth would probably rotate albeit slower about its up and down axis with very little or no wobble. In other words, the eccentric wobble referred to, is a cause and effect of the moon's formation. No collision, no moon forming, no eccentric wobble for the moon to stabilise.
We would still have seasons although they wouldnt be as defined as they are now. The earth's orbit around the sun varies from roughly 91 million miles to 94 million. At the extremes of these distances, summer and winter would be pretty uniform over the planet taking into account we'd have no wobble because they'd been no impact to create it! We'd still have liquid water except at the poles as now, all over the planet even in winter.
Planetary catastrophies do shape evolution as we and the dinosaurs know too well!