> Think of it this way: if you flip a coin 20 times in a row there is a less than 1 in a million chance that every flip will come out heads. Let’s say this happens. Now repeat the experiment a million more times you will almost certainly see that this was a weird outlier and are unlikely to get a second run like that.

Leaving aside the context of the discussion for a moment: this is not true. If you do that experiment a million times, you are reasonably likely to get one result of 20 heads, because 2^20 is 1048576. And thanks to the birthday paradox, you are extremely likely to get at least one pair of identical results (not any particular result like all-heads) across all the runs.