I have to agree with you. We needed JS developers to present our UI to be more reactive/realtime. I am trying this out to see whether we can use Dash 100% without any Angular 2/React code.
Let me know how it goes! One of the cool things about Dash is that if you need to fallback on React code for building components, you can. Here are the docs on building your own components: https://plot.ly/dash/plugins. I imagine that some large teams may have 1 or 2 JS developers that build reusable components that the rest of the 100 analytical python components could use for their day-to-day app development / exploratory data analysis.