But there are other way to give your setting that lived in feel. One technique is before a campaign I make up a list of events. These events are not like a Dragonlance style railroad plot. Rather these events represent what going to happen if the players were not involved. To add the lived in feel add more events that are not part of any plot or ideas you have.I think what might be beneficial for me to take from this, is to not stop the 'History' where the players begin play. But, rather, to push out further with 'what might happen' should they not begin adventuring. Then just modify it as they effect the potential time-line. Subsequently adding 'what might be' to the history with new groups and campaign changes.
Adding this to "The Master Plan" could provide a myriad of adventuring hooks and opertunities...
Best, and may the future be yours to change!