Due to a film schedule that is a wasteland, the upcoming Academy Awards will mostly be awarding films that never saw wide popularity, films that were quietly shot and then sent directly to judges via screeners. So, it's the same as it has been for the past few years. When you add up all the years of Oscar films, you get a fair number of films that did leave their mark on cultural consciousness, including a number based on true stories. Think again if you thought these taught you anything about actual events.
Which would be bad enough if they made these changes in order to make a better story. But nearly always, we find that the true events make for the better story. The altered version instead just makes for the more Hollywood story—more generic, more simple, more easily fitting into how everyone already things these stories are supposed to go.