Why is it so difficult for us to attain a higher form of consciousness? Why is success so rare and brief?
The reason is that the higher consciousness is a divine form of consciousness, and to participate in it we must be in-accord-with divine creation... and not many people are.
Especially given that we must consciously be in accord with divine creation - and also aware of it, and actively choosing it from our true selves (our souls). (This cannot be something unconscious or passive - because the divine is always conscious, always active and purposive.)
Many traditionalists find this line of thinking to be un-Christian, if not anti-Christian; so it is necessary to link it with Jesus. The best source on Jesus is the Fourth Gospel.
In the Fourth Gospel, aside from Jesus himself, the best example of a God-aligned Man is the author of the Gospel, the beloved disciple himself - if we agree that the author is the resurrected Lazarus. The Gospel itself is the product of exactly the kind of divine consciousness that we seek.
A serious question - though - is to do with mortal versus post-mortal life. Clearly we can look-forward to a divine consciousness if we are believers in Jesus as the Son of God and the Good Shepherd who (if we will follow) will lead us to life eternal, with divine qualities that are 'symbolically' depicted throughout the Fourth Gospel.
But why suppose that we ought to aim at divine consciousness in mortal life? And why suppose that our failure to do would be responsible for the most extreme sins of modern life, as Rudolf Steiner recognised in a great prophetic statement of a century ago.
Well, perhaps because that is a theme throughout the Fourth Gospel, a Second Message; if that is what is implied by (for example) the conversation with Nicodemus about being born-again, or the conversation with the Samaritan woman about living water, or the discussion after feeding the five thousand about labouring for that meat which endureth into everlasting life.
It seems that there is a core/ minimal requirement for salvation: believing that Jesus is the Son of God and loving, therefore having faith, in him; so we may follow him through death to Heavenly life everlasting.
This core message is about salvation, and refers to our state after death and resurrection - but it is not about what we should do in this mortal life. Salvation is attainable by anyone who has these core convictions (believes-in and believes-on Jesus), and only by them. However, this gives no guidance for our worldly-motivations during this earthly existence.
However, there is also this Second Message - focused not on salvation but on theosis, on divinisation or sanctification - and this second message is about what we should work-for and strive-for during mortal life. What should motivate us. The answer is that we should strive to attain a new way of thinking and being that is aligned with the divine.
In other words, we ought-to strive for a higher consciousness, by aligning our thinking with the divine and by participating in the work of creation, even before death and during earthly mortality.
And if or when we do not strive for higher consciousness - there will be bad consequences (as we see all around us).