It's not "fairly widely accepted" because there's literally no evidence for it. Anything can happen once. Something happening once is not evidence of how common it is. For that, you need to count how often it happens. We have only the vaguest ideas about how common certain requirements are, and less information about potential hurdles.

That's the point of the Fermi Paradox: if the Drake Equation estimates are right, we should see life everywhere in the universe. The fact that we see no life indicates that our assumptions are wrong.