Does it make sense that a house, any houses or buildings, is built on a single piece of rock?

When you talk to one of your kids, do the rest suddenly stop being your kids?

No, that wouldn't make any sense. When you talk to a child among your children, your attention is on him or her. That doesn't mean the rest cease to be your children.

I'm still unsure as to why there is even a need for a central human authority "to listen to God's voice" when it's been Biblical that the people don't even listen to the prophets each time they are sent. A humanly vessel is proven time and time again to be inadequate. Like you said, what is the point of a vicar when it is God's decision when and where He shall reveal His will? Remember, it was St. Paul who originally persecuted Christians and then converted out of the blue. St. Paul didn't need a vicar to hear the will of God.

Everything in Scriptures points to a trend of decentralization after Christ's sacrifice. The Gospels are documented into 4 books of 4 different points of witness and Acts are letters of several apostles, all of whom were common folks, none rabbis or priests originally.

Even in one of Christ's parables, the dishonest employee showed himself prudent in God's eyes when he found out he lost favor with his master. He separated his eggs to multiple baskets as he relieved the debts of different people.

If Christ had really wanted one of his successors "to hold all the keys", why would he even have called the others? Why would God even send His Son when the priestly nation Israel could have been enough to lead the nations?

One more thing: why did Christ made a point about the pointlessness of a priest who was vain in his obsession with keeping the laws while praising the humbled tax collector who prayed in secret?

If God wanted a vicar why the need at all to show that any secret prayers would be heard by Him?

The truth is one basket is never enough, no matter how hard you wish it to be so.

And isn't it a waste of time to prove that weapons are useful and dangerous? Did God ever have to prove to humans that a sword is a sword, and how to use it to destroy and/or to protect, like we are a bunch of robots? Didn't God simply install his automaton with flaming swords at the gate of Eden to guard it?

Do the common people need to know mathematically why 1 + 1 = 2? No, that would be a waste of time.

"Weapons cause safety" isn't even an argument. It's self evident.