I have deliberately asked this question in the opposite way than usual.
The usual question is along the lines of wondering why the supernatural has receded, why people disbelieve in deity, why God does not communicate with modern Men using visions, dreams, voices and by the 'channelling' of scriptures and other revelations?
Of course, one answer is that God still does all of these things - because some people do continue to experience them. However, plenty of people do not, and cannot, have such experiences; furthermore, those who do have such experiences do not seem to be transformed by them in the way they were in the past. Modern supernatural experience sometimes seems more like a lifestyle choice, hobby, or a way of making a living.
However, what is less often remarked is that these are all 'communications' - I mean, these are indirect means by which God may transmit knowledge to people. All require the use of perceptual, sensory information - which may be defective. Furthermore, these sensory inputs must be interpreted in order to be understood.
Whereas now - it seems - God communicates by directly implanting understanding into the mind, into the stream of thinking. This cuts-out the need for potenitally faulty, errorful perceptions; and cuts-past the problems of misunderstanding.
When God makes himself known by direct means, he goes straight to the limit of capability of that individual. However, this isn't 'perfect' because each person's capability is limited and also distinctively biased. Plus there are the same (usual) problems about communications between people.
Nonetheless, it might reasonably be assumed that direct knowing is superior to the older modes of 'communication'.
If so, why then did God 'bother' with what seems like a worse method? Why did he persist with it for so long?
The answer is apparently that this is related to the evolutionary-development of human consciousness. Men in the past quite naturally and spontaneously perceived God and the spiritual realm.
Then, as development proceeded through the ages, this spontaneous capacity diminished.
Why? Because the divine intention was that Man could be independent of the divine and spiritual - could become able to disbelieve and deny in order that he could freely choose to align with God's creation.
Thus, in his personal development, each Modern Man becomes detached from the spontaneous immersion in the spiritual and contact with the divine of young childhood; and then is able freely to choose to join with the divine plan, to become a divine friend of God - not only a child of God, but a grown-up child of God.
And then, but only then; Man can directly know, can (sometimes, but not in a sustained way) align his own thinking with God's thinking; have his thinking be also a part of the divine thinking.
Can potentially participate - consciously and by choice - in the creative work of God
Note: The above ideas are derived mainly from Owen Barfield, and to some degree from William Arkle - as I understand and have developed them.