js/html games are a pain to develop. I can develop a game much faster with , flash yes , flash and i'm going to stick with that.

Assets are handled , sounds are handled and i dont need to test it on 4+ browsers to see if it works. I get a dynamic strong typed langage, a drawing soft and an animation soft , which is all i need to develop complex games.

- Do i care about mobile ? i can release my game as an native iOs app or air packaged app for android, i get exposure through app stores and can use native device capabilites to enhance user experience.

So yep , it's proprietary , but i chose ease of dev , deployement and fast dev cycles over theorical open-ness and awesomeness.