I suppose that the only way to have a cushion for future gear* separate from any media computer is to have four sets of 7.1 through 9.2 analog inputs. That's a lot of back panel real estate, but might not ever be out of date!

*(When new digital formats are in continual revision and "you'll never keep up." Fifty years from now, will they be beyond digital and into ... bio-plasma conduits? Beyond that, I suppose if they start interfacing with our nervous system, the best home entertainment will have done away with loudspeakers and video screens anyway.)