The Bible is not like a news report. Events in the plot of the story were not being recorded in the moment or even in the days to follow. Rather the Bible is a collection of stories that are told in the present about the past but have the luxury of knowing the future up to the present.
If you are telling a story about the present in the present, it is very difficult to know what is important and what matters and what is not important or what can be dismissed. This is why we have 24 hour new cycles that can say that every little bit of news is "breaking" because we don't know if this newest bit of information is important to the story or not. Because we don't know the future we don't know what is important to hold.
However if you are telling a story that is set in the past, you have the ability to edit the story and change the story in order for it to make sense in the present. You can leave things out that don't matter as much. You can edit what is said or what was done in order to "get to the good parts". It is like when we DVR a show on television. We can fast forward through the commercials because they do not pertain to the story - but we cannot fast forward in the present.
It is important to remember this when reading the Bible. The authors of the stories are writing with a luxury of knowing the future in relation to the setting of the story.
So when a character in the Bible looks like they are predicting the future, in a sense the can because the person writing the story down knows the future that the character did not know. This does not mean that Isaiah or Jesus were any less "prophetic" it means that the storytellers are doing everything they can to convey a message that is more important than "this person could predict the future."