I believe its was Hoyle and Wickramasinghe who calculated the probability of the first protein molecule to be on the order 1 in 10^120.
I don’t know about those two and I’m being lazy in not looking them up, but, seems to me the first question is “What first protein?” Proteins are chains of amino acids. Reasonable speculations indicate a whole slog of aminos in a pre-biotic Earth environment. Doesn’t seem to me to be so far fetched that two such thingies glom on to each other and viola . first protein. Probably doesn’t do much except float around looking for more candidates to join with.
10 to some big number seems a bit linear in thinking, doesn’t it? If we’re talking some large mega-protein like hemoglobin then I can understand the incredulity of its spontaneous generation, but, I hope this is not what is being offered here.
Cannot a simple chain of, say 5 aminos, or maybe even 50 aminos, not be considered a protein? The incredulity certainly lessens at this level. And if we take the reasonable assumption of many millions of trials daily over many millions of years, does this not lessen it even more?