Future-proofing surround sound

Home theater surround sound is currently transitioning from 7.1 to 9.1 which has the drawback of needing to re-encode all 7.1 content. The following idea would make audio content independent of the number of speakers:
[...] record where the audio is supposed to come from, instead of which speaker it should be played on. This way a movie would never need its audio remastered again, because the fact that the plane coming in at 2 O'Clock wouldn't change no matter how many speakers you had, it wouldn't even matter if you had a speaker placed precisely at 2 O'Clock. So basically your AVR [audio/video receiver] would render the audio on the fly based on the number of speakers, and where you placed those speakers by using the recorded sounds and the data about those sounds.