I think the main stumbling block for me is the perception of time scales. It is impossible for me to say, with certainty, any information regarding time scales

I think the main stumbling block for me is the perception of time scales. It is impossible for me to say, with certainty, any information regarding time scales of a billion years and the randomness which permeates the evolutionary process. What we see and know are the winners of the race, not the mountains of failures.