Well, without wishing to get embroiled on an archaeology list in a
discussion on this, its worth bearing in mind the immortal Spock words: "its
life Jim, but not as we know it". I am not sure that we really should be
terracentrically only of life forms which look like us and have the same
type of metabolism (though of course that is precisely the assumption made
by von Daniken in most of his identifications of "pictures of spacemen").
If the majority of astronomers really do think as you suggest, I would
appreciate some references, as I am clearly out of date as to what the
consensus is - but then isn't the SETI program still being financed?