There are what, around 8 million species of life on this planet alone and 90% of all known species are now extinct. That’s over over 700 million species on this one ball of rock.<quoted text>
The odds that life exist elsewhere in the Milky Way? Are pretty much 1:1.
Water and carbon are the main prerequisites for life
There are several other galactically local planets known to have water (hence oxygen) and carbon with more being discovered every week.
Given these facts then to say that life cannot exist beyond earth is terribly narrow minded.