halbhh
The wonder and awe of "all things".
According to the scripture about that very question, the intended outcome God desires is to see which people can trust Him *without* seeing Him, the goal called 'faith', which can be thought of as a strong form of trust. It's valued. Possibly because faith allows an intelligent being to sustain love and avoid conflict in a love relationship over very extended time periods (not merely years or merely decades), by hoping for the good even when its not visible at this instant, for example. So, 'faith' is the stated purpose/goal of life here -- for instance according to the words of Jesus of Nazareth -- to believe even without seeing.If God cared about everyone believing God would reveal to everyone individually.
Since God does not care whether we believe in God or not this does not happen.
God only cares if we are virtuous
So, if instead God simply became visible, then that would preempt the goal, prevent the sometimes accomplishment of the purpose of life here. That stated purpose includes to believe in God -- trust in the ultimate Good (without seeing) -- and to learn to love our neighbors as ourselves, even if they are not like us.