Second, there's no barrier to entry there. Facebook's ~10000 engineers can recreate features with amazing swiftness, do it better than the first movers, then spread the feature quickly through its 1 billion+ user social network. If Facebook wants to beat snapchat at the AR game, they will do it when they feel like it.
https://techcrunch.com/2017/04/13/instagram-stories-bigger-t...
It's not just creating a feature, it's understanding why someone would want to use it. That's the difference between a product and a business.
Most of HN is too old and otherwise not the Snap demographic. How many of you actually use Snapchat with your friends and watch the videos with your headphones in? The experience is key -- the business facets being analyzed are a symptom of the experience.
Snap's entertainment experience puts the viewer in the center of the action, similar to VR 360° experiences and Spectacles is a direct expression of that understanding. Snap's AR advertising (sponsored filters) has been an overwhelming success. I don't think a real competitor has emerged for Snap yet, as long as they stay the course.