Something that comes to me with increasing force, is that plenty of people - including self-identified Christians - don't really want what Jesus offers; at least not what he offers in the Fourth Gospel, as I understand it.
I have concluded that theism (belief in the reality of god/s - whether explicit or implicit) is just essential to be a functional human being; it is almost a biological requirement. Because, since humans have evolved in a religious context, to subtract religion from a life is for that life to be in a pathological state.
Biologically, this is most often seen in the chosen sub-fertility of aethists in atheist societies, and the adoption of values that reject family - even as an ideal; both of which are covert forms of personal and species suicide.
(I am, of course, generalising - there are exceptions; but these exceptions are exceptional, i.e. rare.)
But most theists are not Christians, the motivations associated with theism are various - and only some (few?) theists are Christians.
To be a Christian is both personal - about Jesus as a person; and associated with a positive attitude to The Body - regarding incarnation or embodiment as the ideal state to be, forever.
Jesus in mortal life was a person, an embodied Man; and in eternal life he remains a person and an embodied Man.
Jesus's offer is aimed at those people who want for themselves (and hope for those they love) eternity as embodied persons: that is what resurrection means.
So, although Jesus is here-and-now as a spirit (i.e. the Holy Ghost) - this is not Jesus's full nature nor his offer for life everlasting.
Jesus is not a spirit, nor an abstraction; not a force, nor a field; not a vibrational-level, nor a frequency. Jesus the person is not everywhere equally at all times - not present in all things...
Instead Jesus is actually a physically embodied divine Man, actually present in some place at a particular time - no matter that his spirit is everywhere available: a person who is also a fully-creative god. And Jesus's offer is for those who want to join him in such a life.
Therefore, it does not surprise me when not everybody wishes to be a Christian. Because it seems clear that not everybody wants what Jesus offers.
But plenty of people do not know what Jesus is offering. Plenty!
Some people have changed their concept of Jesus to correspond with what they do want. But this is not to be a Christian, but to be something else that does require God but does not require Jesus. Such people are, in effect, re-naming their deity as Jesus.
This is a mistake in naming, but it may not be a mistake in terms of what they want. I think many self-styled Christians - now and in the past - do not like mortal incarnate life, and they regard it as a mistake, a misfortune, merely a time of trial...
And they want to live as bodiless spirits in an eternal, unchanging, bliss - without any awareness of the self - ceasing to be a person. In effect they want to be re-absorbed back-into God. As if incarnate mortal life had never been...
But the real offer of Jesus was simple and child-like: Jesus (the person, the divine person) says 'follow me' (and to follow him requires trust, faith, love)... Follow me and I will lead you to resurrected life in Heaven.
And this Heaven will consist of other people who also want this.
It is an offer so simple, child-like and clear that it is almost incomprehensible!
But an offer that does not appeal to all - and perhaps does not appeal to many...
But there it is.