[cwillu]

“Wouldn't” is being used in the logical-conditional sense, not in the sense of willingness, requesting, nor opinion.

It's literally “What's the reason that the machinery of the brain doesn't use this mechanism, given this proof that the effect could in principle be used?”. A similar question can be made for quantum mechanical interference in the brain (which to be clear I feel is adequately answered by “the brain is a wildly inappropriate vehicle for harnessing interference effects).

[mykowebhn]

Using your explanation, let me try this on an example, say the extinction event that killed off many dinosaur species.

If some mammalian species were able to survive this extinction event and subsequently flourish, why wouldn't dinosaur species?

Not sure that works for me. I'd put "couldn't".

[cwillu]

It may not work for you, but you're literally arguing with the dictionary here.