In Statcounter, it shows that IE still takes 35.75% users of the world.
Asia even worse, IE takes 76.89% in China, 64..46% in Taiwan,
the most advanced country is Japan, still 54.36%.
In these 2~3 years, can you make a decision to spend millions of money to make/maintain a mmo, and prepare to tell your investors: "Hey, guess what? more than 40% users can't see our game!!" ?
As for Flash, mmo was an already done game genre. You can check this old famous game:
By far, HTML5 is just showing it can do something Flash can do in some experimental ways;
however, the chance of future will never on PC anymore. The real value of Mozilla's BrowserQuest is that it can be played both on PC and none-flash Mobile.
That's why AIR 3.2 so scary! It will take the superiority of HTML5 away!
I know I am not an optimist, but maybe one day we'll cry and beg an AIR exporter soon.
Frankly, if I can make 50,000 USD, I won't care it's 9% or 30% fee.