I didn't say multiple site changes can't occur. I said evolution doesn't typically require multiple simultaneous changes.
Your mathematical model is based on shuffling the entire deck for each generation. Evolution accumulates small changes. Each viable generation will have few changes from the previous.
It does not require astronomical odds to explore all possible changes, one at a time.
"It does not require astronomical odds to explore all possible changes, one at a time."
That's incorrect, mathematically (this point is not arguable). Math doesn't care if you make your changes one at a time or billions at a time; the probabilities for achieving a desired sequence are the same.
To wit: fliping one coin at a time or flipping a billion coins at a time will have the same mathematical probabilities for achieving a specific 1 trillion length sequence of heads/tails.
However, what can change the above math is external bias.