From the OP
The genius of Charles Darwin was in recognising the power of natural selection as an accumulator of small random changes.
Imagine our 10,000 monkeys randomly typing until one of them by pure chance comes up with "When.."
At that point all the other pages are scrapped and every monkey is given a copy of this page. We observe some more until another monkey adds "shall.." and so on through thousands of iterations. How long would it take to achieve "When shall we three meet again? In thunder, lightning, or in rain?" Completing the full play now becomes inevitable.
Evolution is a little bit like that.
Let’s look at this from another angle.
How much complexity can random processes reasonably find in a finite amount of time? (Random process first have to find something before it can be selected for.)
If you have a keyboard of 26 English letters and a “space” bar you have 27 possibilities at each location.
That means to get the first word “When” it would require on average
27x27x27x27 attempts
Thats 531,441 attempts required. With 10,000 Monkeys typing that’s only 53 attempts per Monkey, so that’s easily within the reach of chance.
However to get just the first two words together “When Shall” the odds become exponentially more difficult.