Based on my personal experience: The reason why is probably because of the poorly documented, unstable spaghetti code their public libraries consist of.
Which confirms GP's original idea. There's a fine line between an API that is full-featured and one that can be learned in an afternoon. Plotly is easy to work-through. But if you're aren't comfortable digging through its source code the documentation won't help you. Furthermore, it seems like their support / hosted solution is less for hackers in need of a helping hand and more for completely non-technical users that won't touch JS with a ten foot pole.
Yeah well - looks like we disagree. :)
- Plotlys api is def. not full featured - more like a proof of concept (unless you are building generic 2d plots).
- If you can’t use the api without reading the sourcecode: the api is not documented.
- The 3d libraries only work with the simplest use cases. Its pourous, unstable and inconsistent. Like a poc or alpha.
I am a “technical user” and its bc. of projects like Plotly I try to avoid js (pole or not).