Blueray supports downmix metadata that I think lets you mix volumes with the full 6x2 matrix, and I don't remember if there's EQ but there may be. Also a 5.1 AV is like 500 bucks if you have the space. I don't think what other innovations you need. The technology to stream different audio streams and let the user choose is there.
Thing is most studios now do only one mix for theaters and also most streaming providers don't give many fucks about audio. It's not an innovation problem it's a product problem.