I'm guessing it's a money thing. After all the RR2160 has USB-B input for streaming from a computer so you know they have the circuit and the software to support the feature.

FWIW I too will be passing on the 976. The jump to 4K is going to be a long and pricey transition and I can afford to wait to see what comes next, at least for now.
_________________________
975/7075/SMS-1
Aperion Verus Grand Towers & Bookshelves, Verus Forte Center, Infinity Surrounds, Ultra-X12
Oppo BDP-203, XBOX360, Xbox One
LG 65" OLED
RR2150 w/Klipsch SCR-2