Because although Jesus was God, he was also a man - 100% human. Human beings cannot be in more than one place at once - not physically possible. That's why, as I have already said, Mary and Martha both greeted Jesus with the words, "
if you had been here my brother would not have died".
WE know that Jesus stayed away so that he could perform the greater miracle of raising Lazarus from the dead; they didn't, not at that time. If Jesus had physically been with them, they believed that he could have healed Lazarus and prevented him from dying. As Jesus hadn't physically been with them, he did not do that miracle for them, and their brother died.
At no time while he was on earth was Jesus in Jerusalem
at the same time as being in Capernaum,
at the same time as being in Galilee - didn't happen.
After the resurrection, with his resurrection body - yes, maybe. But before the crucifixion, no.
Could he multiply a few fish and loaves into dozens?
Actually it was God the Father who performed that miracle - Jesus gave thanks to God and the miracle happened.
Yes. That was a miracle - a one off.
Could he pass through doors?
No, not before the resurrection, with his human body.
You're going to tell us what Jesus can't do?
No, I'm telling you that when he was on earth he was 100% God AND 100% human. The author of Hebrews says that he was like us
in every way, except that he didn't sin.
After the resurrection Jesus had a new, resurrection body, which could eat fish and be touched, but could pass through doors and probably be in more than one place at once. He stayed on earth, in this body, for 40 days and then ascended to the Father. The next time he is physically on earth as a human being will be when he returns as king - this is the teaching of Scripture and I see no reason to not believe it.
Of course he is present with us and IN us now, by his Spirit; that's not in question. Because of this, Christians can be in any number of places and countries, teaching and healing in the name of Jesus. Whether we are in school, in hospital, in prison, on the mission field, in the convent, pulpit or study; whether in Europe, America, Asia or even on the moon, Jesus is with us -
by his Spirit.
Apart from anything else, logic should tell us that if Jesus was here physically, in person, someone would have seen him.