I will note that while 20,000 chemical compounds sounds like a lot I don't know that is true. Aren't there hundreds of compounds in an orange? I do agree with

I will note that while 20,000 chemical compounds sounds like a lot I don't know that is true. Aren't there hundreds of compounds in an orange? I do agree with the conclusion though, we likely have tasted (or could have tasted) weaker options over the years. I wonder if the real conclusion is "we don't understand the human body enough to predict what will work so getting lucky is our only option".