I never know what to think about these posts. As I've mentioned in other comments or posts around similar topics, I've had a successful eBook and still do. But when I'm asked for advice, I'm not really sure what to say. It just feels like dumb luck sometimes, honestly.
Certainly a combination! Here’s a study I think every child should be taught, where they created artificially compartmentalized worlds for new music. They found:
1) many songs had almost no downloads in any world. They were “truly bad“, and avoiding that is the skill
2) amongst the non-bad, different song is went viral in different worlds. That is the luck.