The odds of life only ever happening on 1 planet in over 13 billion years, across billions of galaxies, which each have billions of stars would just be unbelievable, I mean really think about those numbers, thats a lot of space and material for life to happen in quite often, even if you only got life in 1 spot in each galaxy that would still be billions of places life happened, think about how big the Milky Way is, and where just an average size galaxy, and there are billions of other galaxies out there, like I said in a previous post, there are more stars in the Universe then grains of sand on the beaches of Earth.
You are assuming life is easily created (which it may be). What if life is incredibly complex and requires a large multitude of variables to start?
For a rough idea of my point, let's say creation of life on a planet requires 10 variables aligned to spark life, we'll assume the spark ignites and grows (hm). We'll also assume life doesn't get wiped out by an act of god (astroids, gamma rays, etc.)
Even with those odds, I would agree, life probably wouldn't be so rare.
Now increase the variables, move it up to 1000 properly aligned variables. Now start factoring in the universe pilot wounding your young life forms, astroids gamma etc...
The fact life has existed on Earth for this long to produce intelligent life, could be against incredible odds.
Without knowing the size, age, or even amount of dimensions in our universe, and without knowing if life is rare or not, a large universe does not have to increase odds for other intelligent life forms.