This would be the domain of linguistics, and my understanding is that there's really no clear consensus on anything. Folk etymologies are rarely any better than

This would be the domain of linguistics, and my understanding is that there's really no clear consensus on anything. Folk etymologies are rarely any better than a "just-so" story, and often they're an entirely fabricated re-analysis. When we talk about the creation of neologisms like this, we often put them into various categories: sometimes they're simpler than the previous idiom, sometimes they're more complex/nuanced, often they can act as some sort of shibboleth, but it's all after-the-fact analysis, I don't think there's any real rules.