There have been three general elections since the Iraq war.
Turnout has gone up at each of them.
It doesn’t get mentioned because it is an inconvenient fact.
It doesn’t fit the habit of pro-democracy campaigners who, in the UK, spend nearly all of their time knocking the state of democracy as if pessimism is the required qualification to join their club.
It doesn’t fit the story left wingers like to tell about the Iraq war and political disillusion.
And something that’s been happening for three elections in a row is still a little too new for political scientists and textbook authors.
Which all helps make ignoring this fact so deeply ingrained that despite being public and obvious, it’s also ignored, neglected and treated like it doesn’t exist.
UPDATE: This pattern held in 2017 too. Make that four elections, each with rising turnout.