Miracle births happen a few times in the Bible. There is John the Baptist, Jesus, and Abraham and Sarah who had a child in old age. When there is a miracle birth, it’s so God can do something special through the child. Samuel is no exception.
Hannah was very troubled by the fact that she could not get pregnant, but God had something important He wanted to do through her. God has plans we know nothing about. Maybe what feels like God withholding something from us is actually God setting the stage for something greater. Can we have the faith to ask God for something and then just wait?