It wasn't so much that video streaming was the only thing they bothered with as video was the only thing they could come to an agreement. When it comes to more interactive elements, there are such entrenched interests that consensus was impossible As it is now. What are you going to use to replace Flash that (a) isn't buggier then Flash (that removes JS and Java, both error-prone), (b) that everyone will agree to, and (c) won't get hijacked by some entrenched interest down the road?