I'm one of the few who doesn't. Unless someone asks me about such topics or I'm using the afterlife and existential questions in a story, I don't think about it. I don't see the point. There's no way of knowing what holds for you after death. So why dwell on it?
I understand what you're saying. And, at first, it makes sense that one would need spirituality to be able to connect with a spiritual being. But, if God is all powerful, why is he limited to the spiritual realm or world or whatever? It didn't seem like he was in the Bible, what with visiting people and sending angels to scope places. Secondly, children are wrong about a lot of things. If I humbled myself to the point where I was as intellectually inept as a child, what other useless junk would I still believe? Santa? The Easter bunny? The Tooth Fairy? That the toilet was a magical, bottomless well? Allah? And how would I be able to differentiate between the truth and the Santa Clauses?
Characteristics, I guess that you have watched Startrek, and are no stranger to the notion of alternative dimensions. A good way of understanding the kingdom of Heaven is to consider it as another dimension. It is unbiblical to just consider it to be a place we go after we die. Jesus made it clear that the Kingdom of Heaven was near to us, and accessible.
Many Christians freak out at such thoughts of dimensions, but it makes abundant sense and matches a whole load of scriptures.
Now, I know that the bible cannot and should not be used as a proof text for someone who doesn't believe its authority, but hang in there for a moment. When God created the earth, and Adam and Eve etc....... (Before I continue here, if you believe in a creator God, then you have to allow him to be powerful enough to do all sorts of "magic", rather than the earth just making itself, otherwise it is pointless continuing.).....God created the kingdom of heaven and the earth as a single existence, a single unified dimension. Adam and Eve were enjoying the Garden of Eden, or Paradise. This is the same Paradise that Jesus told the thief on the cross that he would go to with Jesus.
As an act of love God allowed Adam freewill. However there was one thing that He warned Adam about, and as I am sure you know, it was not to eat of the Tree of Knowledge of Good and Evil, otherwise he would die. I should add here that there was another Tree that Adam most certainly could, and should have eaten. That was the Tree of Life, which represents the freely available wisdom of God.
Now God was not threatening Adam that He would strike him dead if he ate of the wrong tree. God was just making it clear that there were fatal consequences for such an action.
So what was wrong with this Tree. The name gives it away, along with the words of Satan's temptation. For God surely knows that in the day that you eat of it, then your eyes shall be opened, and you shall be as God,
knowing good and evil (right and wrong).
God had given Adam dominion over all the creation, but that dominion was obviously under Gods higher dominion. Adam was created to walk in close unity with God and up to that point was in full spiritual relationship with God. The temptation of Satan was quite specific.
Satan was challenging Adam to take charge of the planet himself, using his own reasoning power to work out what was good and evil, or right and wrong. Adam was choosing whether He should become the source of life and direction over the earth. Adam was choosing to dump God out of the equation. In doing that Adam was letting go of the Spiritual communion with God.
This is exactly what Adam did. In doing so, his spiritual nature immediately died, and he lost communion with God.
The Hebrew scriptures in Genesis make this clear. When God warned Adam, "you shall die", if you eat of that tree, the Hebrew words are more accurately translated as,
"in dying you shall die." Some bibles show this in the margin notes or at the bottom of the page. It is clear then that there is a double death sentence being pronounced. This is why Adam wasn't killed outright. However he most certainly did die spiritually, and thus death became a part of this creation. Added to that, in obeying Satan, Adam bowed down to Satan's wisdom in preference to God's. Thus this planet became part of the jurisdiction of Satan.
This is why Jesus called Satan, the God of this world.
Adam's regretful choice is the answer to your main question, if God is so powerful, why is he limited to the spiritual realm? God gave mankind freewill. Mankind chose to get rid of God, and repeatedly chooses the same. According to the bible, shortly after Adam's unilateral declaration of independence, God divided the created order and the spirit realm and the physical realm were now separated by a gulf. God always gives man freewill to choose.
God is a spirit, we are flesh and blood. Flesh and blood cannot see or hear God. It is only with our spiritual persona within each one of us, that we have any access to know God. If we are proud and arrogant with our intellect then it is impossible to hear or discern anything of God.
Regarding your comment about the foolishness of children, remember that it is adults in their human intellect who teach children about Santa, the Easter bunny and the tooth fairy! I am not suggesting that you adopt a child's intellect, but that for the sake of listening and hearing, you subject your intellect below your quiet spirit, rather than above. A young child has his intellect and spirit of equal worth, unlike adults.
If you really want to know something of God, then be prepared to be humble, and acknowledge him for who he is. If he really is the creator, and you are created, then he is somewhat different to you. God promises wisdom to all who ask, as long as they are willing to receive. Just a word of caution, don't expect a booming voice over the canyon. The reason I said to quieten your intellect is that it is an enemy to your spirit persona, and will make it almost impossible to hear the still small voice of the Spirit. Also God many times answers using the common things around us, but it still requires humility to comprehend it.
Sorry to be long winded, I hope it casts some light as to why we don't see God plain to the eyes like we see everything else.