As many stars and circling planets as there must be in the universe, there has to be life of some sort out there...Some are possibly equal to what has lived on Earth for millions of years...Some are way behind our times and some are probably way ahead of our times...IMO, the Earth being the ONLY planet with life is basically impossible....
IF alien life exists and IF they traveled to earth they would be able to roll over us pretty easy considering the technology they’d have to have.
That’s the way I look at this issue, simple logic would say with all the billions of universes out there, each containing billions of stars and around those stars are perhaps trillions of planets, some of those planets may have intelligent life just forming like humans on earth, other as you say maybe roughly equal to humans on earth and others may be millions of years more advanced than humans.
To say the earth is the only planet in the universe that contains intelligent life simply doesn’t seem possible to me.
Chances for carbon based life as we know it really diminish when one filters out the majority of stars which are unsuitable for supporting life as we know it.
Of the stars remaining, another reduction is required for those not existing within a galaxies habitable region.
Then we have to apply all the criteria for getting an earth like planet, with an earthlike tilt and an earthlike orbit and having an earthlike moon.
Then there is the matter of how in a primordial sterile atmosphere could the necessary chemicals come togetherr at the right place and right time for life to begin?