I don't know about that, I worked on the React team full-time for several years and just got to 86 before getting tired and stopping. I imagine most of my former colleagues also know more than 1.

Unfortunately Facebook, the flagship React application, does not reflect that.

I just loaded facebook.com and saw 30 unique elements used on my homepage. Seems reasonable enough.

I opened up facebook.com and clicked Inspect Element on a random comment Like button. It’s a <div> nested inside 61 (I counted) layers of <div>s.