Simply, because it cannot do so.
Science, as we know it today, is trying to take a look, from the outside, into various phenomena through its own measuring and calculating tools. The researcher is well trained to remain as detached as possible, emotionally, from the research process in order to maintain "objectivity" as much as possible. This stand point is believed to keep the process "clean" from unwanted distractions what may improve the odds to get "true" or "reliable" results.
This attitude, that comes from a deep rooted influence of left brain approach to study and research is what stands between today's science, and humanity in general, and understanding one of the most important asset people possess and may use to improve their life substantially, their intuition.
I may summarize this situation by saying that today's science is mainly a left brain science. We demand clear proofs following very specific standards before we agree to accept new findings. And we have good reasons for this. But this approach leaves us working mainly with just half of our resources, at most. As long as we don't involve right brain ways and tools to explore and understand our reality, many of the things exist will remain obscure and hidden.
One cannot truly understand imagination without imagining. One cannot truly understand all experiences without experiencing them first, at least partially. Can we really learn about love without loving? No we cannot. You cannot truly measure things solely from the outside, without getting inside, and then say you have the whole truth. This way you will remain blind
One cannot explore intuition without being intuitive. One cannot get many of its characteristics while remaining too skeptic about it. One cannot really explore many of right brain's properties, only by using left brain tools. It's like trying to understand Chinese while knowing only English. Left brain is not capable, all by itself, to learn all about right brain. The "local language" of right brain, made of emotions, intuition, imagination and creativity is pretty strange to those who rely heavily on left brain nomenclature.
As long as research is working this way, doubting the validity of many of right brain's properties like intuition as reliable source of knowledge (as long as it not proven by its strict standards), and this what happens as long as you do not learn the language of right brain, many important parts of existence will remain in the dark. The funny thing is that left brain answer to this claim will be: "well, can you prove what you just said?"