So a bit of research. In May 2009, MK closed at 9PM on 10 days, 10PM on 12 days, so over 2/3 of the month, it was closed by 10PM to everyone. It was open until 11PM only 3 days, and 12am - ZERO days. I did not count ANY days that had evening EMH for those numbers.
This month - May 2016, MK NEVER closes at 9PM, and closes at 10PM ONLY 2 DAYS all month. 11 days it closes at 11PM, and 14 days it stays open until 12AM - without ANY evening EMH days counted. So this year MK stays open until 11 or 12 for 25 days of the month for everyone.
You are missing some key factors in your analysis, though.
You are looking at historical posted hours. At the time period you are talking about (2009) Disney had a practice of posting severely cut down posted hours, but would extend the park hours the day of or the day before. These were updated on the Times Guides handed out but didn't get retroactively corrected online. They can't do this anymore because of MM+ and all the advance scheduling they are asking people to do.
Beyond that, this is also the start of the summer season.- so yes, operating hours are longer. They always are. But much of the year, they aren't. Going back to 2009 is interesting, but if you go back further - MK used to be open late nearly every day, all year. They didn't need "EMH" because everyone who bought a ticket got the same operating hours.
Yet, admission prices have skyrocketed in unprecedented amounts.
To put this event in perspective - $50/hr used to get you A PERSONAL GUIDE CM to escort you through the park.
To those that don't see us sliding down that slope, who don't realize that if this was designed to further reduce hours and eliminate EMH, you are absolutely dreaming. If this had been successful, you would have seen it by the end of the year, no question. And even though it seems this event fizzled, you can also bet that they aren't done trying.