ben0 made a good point - a large business won't look favourably on not being able to support IE 6, 7 and 8, whereas for us that's not such a big deal (according to StatCounter, those users are only about 15% of the web now). Large companies have much different priorities.
I agree that it's early days for HTML5, and mobile HTML5 is especially problematic - but that's why we're working with directCanvas and CocoonJS, which should smooth out all the bumps on mobile and bring better performance too. Maybe Wooga should have tried those out too, but they say they started in 2011 so that might have been before either was available.