I've only seen one sponsored HTML5 project from stencyl.
My doubt still is:
Regardless if the game is Flash or HTML5 the portals that these games are published are the same.
So, why, the examples you have presented, do they still prefer Flash to sponsor?
It will be because are there still developers and good games Flash?
It will be because they still use the same APIs?
It will be because players' browsers still accept this?
Or is it just you (Which practically works with miniclip as the thechaosengine commented) who thinks they have no interest in HTML5?
Because I do not see any advantage continue with Flash.