In short, a CD encoded in 16/44 has no information beyond those bits. Interpolation is not finding something that's there; it's guessing at the existence of something and adding it.
24/96 encoding on the other hand is a real advance, and of course a 24/96 dac is necessary to fully decode these recordings. However, other factors in a dac design may not allow all those bits to come through as musical information: if the dac is not well designed, noise, for example from the power supply, or jitter, will nullify the advance represented by 24/96.
That is partially why a well-designed 20-bit CD player w/a quiet and dynamic dac and output stage will probably beat a cheap nasty DVD player with a 24/96 dac.
24/96 encoding on the other hand is a real advance, and of course a 24/96 dac is necessary to fully decode these recordings. However, other factors in a dac design may not allow all those bits to come through as musical information: if the dac is not well designed, noise, for example from the power supply, or jitter, will nullify the advance represented by 24/96.
That is partially why a well-designed 20-bit CD player w/a quiet and dynamic dac and output stage will probably beat a cheap nasty DVD player with a 24/96 dac.