Giving someone or something a name signifies possession. When a child is born, he is given a name by the parents. It is as if the parents are declaring their ownership rights. Likewise, when a company is developing a new product, a name is given. Even projects are given names, even though no products may be involved. In the Bible, we see that King Nebuchadnezzar gave new names to Daniel and his friends, ostensibly to show that they belong to him now.
One might say that God started it all. In Genesis 2:19-20, it says "Now the LORD God had formed out of the ground all the wild animals and all the birds in the sky. He brought them to the man to see what he would name them; and whatever the man called each living creature, that was its name. So the man gave names to all the livestock, the birds in the sky and all the wild animals." This implies that God gave mankind dominion over all the animals and all the birds.
Now, when a child reaches the age of 21, he declares himself an independent adult. Why is it that he doesn't get a new name to symbolize that he is no longer under anyone's authority? Should he? Would he? Probably the answer is "no", yet many at that age behave like they have a new name.
And for the ladies, here is something to think about. By Western tradition, the woman gets a new name when she gets married; her husband's. What do you think of that?