What Dolby PLIIx, DTS Neo6, and other surround methods do is extract the acoustic signature that a venue adds to the music from the stereo track -- they don't make something from nothing -- and redirect it into the proper channels so your home system can more accurately recreate the acoustic signature of the venue.
That being said, music, as always, is a hobby chock full of personal taste, opinions, and choices. It's not old fashioned to stick with stereo if that's what you prefer. It's a preference -- no more, no less.
