"I can think of no good reason why natural selection was not operating right from the word go..."

Then think a little harder. Natural selection requires self-replicating entities to "work" on. If that is the case, natural selection could not, by definition, have created self-replicating entities from entities which did not self-replicate.

"Your description is a little abject ..."

I described nothing; how, then, could my description be abject?

"Perhaps you think that we atheists are incapable of appreciating all that."

I did not know you were an atheist; equally, you do not know that I am not. What on earth has atheism or its lack got to do with this?

I made no explicit reference to "complexity and beauty and diversity" because my argument does not involve them. Your introduction of them is a red herring.