Dec 4, 2016
I'm pretty sure it's because it cannot connect to two pairs of VI300. If you try and connect a second pair it will just boot the first pair off. I don't know if a future upgrade will allow pairing 2, but it's not just about decoding, I think it would just replicate the rear left and right through a second pair. Think of a wired amplifier. You can wire in 2 speakers to each input and have 10 speakers, but it would still be a 5.1 output no matter what the input source.
Part of that would be that there are still variations in standards for 7.1, so Bose go about it a different way. Instead of adding extra speakers they use reflected sound to provide that immersive experience. With the 300 you already have sounds coming from the sides of the room due to the Phaseguide speakers within the bar. If you want more immersive sound go for the Lifestyles
Jun 7, 2017
Still curious what the ST300 would do practically if you try to do, as the ST300 seems to work with 2 AM300 Subwoofers,without knocking out one of them.
Though technically it is way more easy to play 2 Subwoofers, even if they're using the same channel. for the IV300 this might end up in 4 speakers playing only 2 channel which will be much more noticable and not satisfying.