I think the franchise just lost it's novelty value. There wasn't really anywhere to take it that could expand the experience in a meaningful way. I remember loving the GH games and playing the shit out if them for years, but I also remember them going stale and boring because it was always just more of the same simple game mechanic with a new background track.
The rosy red glasses of nostalgia is making us biased.
About 0.1 banana