A timeline is just that, a time line. It is a vosible diagram that shows what events have taken place and the time frame the events happened. Some timelines are more accurate than others.
A timeline can be accurate on dates and what events have taken place on that date, However, the time is not so accurate. Time, most generally, is estimated especially if an event of some kind,for example,a show,given a time to start but does not start at the time stated. The show that is scheduled to start at 7 pm may start at 7:15 or 7:30. Timeline will state that the movie started at 7 pm. After the movie, drinks and snacks will be served. As you can see the timeline stated the present, the show, and the future such as the time for drinks and snacks.
Timeline for a more accurate explanation to determine an outcome does not foresee the future. We can put down what and when something happened but can't state what will happen in the future. The future, I think are goals that need to be met at a certain day and time. As we all know that time is never specific. Time is estimated and nothing ever starts on time. Timeline for the future is like an assumption of what will happen and what time?
The past tells us what has happened, the present tells us what to expect to happen, the future is what one plans to do at a particular time. The future is open for change and more than likely will be altered by something that happens in the present. Timelines reminds us of the time of events and the places if you wanted to know of another event and time. That helps narrow down when and where of something you want to remember. That is my explanation.