It's surprisingly easy to accidentally be designing a game and not realize it. And designing games is hard. And one can closely approximate the percentage of the population that's put so much as one thought toward how to do so—the limits of the practice, the balance, the ways your rules can be abused or encourage behavior you hadn't anticipated—ever, as zero. That when someone starts to recognize what they're accidentally doing they tend to give up, or abandon any effort to do it well, or ditch it and go with some familiar, proven pattern instead even if it sucks and doesn't fit the situation, makes sense. It's hard, and very few people are good at it.

It's easier to recognize that you're playing one than that you're making one, it seems.