Not sure on the HD remake side of it all. I'm sure someone high up at Square Enix said the cost and time it would take just to make a FF7 was quite a lot, and is the main reason they haven't done it already.
Maybe it has something to do with releasing them on PS4 or something? Sony patented some sort of retro achievement thing which also allowed them to set scenarios on old games or something like that.
Or maybe they just thought it'd be nice for fans
