Logic would dictate that a global society capable of mass communication and a more educated population would make it harder to "rewrite history." Does this actually play out in the data?
For example, is the history of say the United States or Great Britain more accurate over the last few centuries as compared to 1000 years ago?
To some extent that is true. When you read the answers on this sub you quickly see the difference in the kinds of questions specialists in different periods can answer. I can explain exactly what reviewers, audiences and censors thought of a modern film whereas it is really hard to do that for classical drama. There are new problems however. The biggest is that we now have archival collections measured in kilometres so it is impossible to read everything. We also still have to make the imaginative leaps that are necessary to turn history from a record of facts into an analysis of what those facts mean. Having more evidence doesn't necessarily make me a better historian.
The other problem is that our subjects are also from more complex worlds. Modern government and societies are so big and change so quickly that is very hard to master the evidence that a minister or president used to make a decision. It remains very hard to know which advice mattered most. Look at the attempts to analyse something like Iran-Contra and you get a sense of how hard contemporary history can be.