In my experience, when people say “system doesn’t matter” what they really mean is “other peoples’ systems don’t matter.” They already have a system in their head — they have a game they know how to play and that’s what they play. They don’t need a new game that tells them to do everything differently in ways that make them feel weird and uncomfortable. All they need out of game designers, writers, and publishers is some toys to make their own game/system more colourful.