Xiph used preemptive approach and refuted all accusatoins and patent attacks on Opus as soon as they surfaced, which helped its acceptance in IETF. They plan the same tactic for Daala which hopefully would kill all the FUD. That's in contrast with VPx where Google waited for lawsuits instead of defending it right away and refuting any false accusations.
However IETF acceptance doesn't mean that the likes of Apple will actually start using it. But making it mandatory for the video tag would be a big victory, since those who refuse to support it will be under pressure to follow the standard.