I think fashion does come into the equation if only because it will be easier to find people who can grok the code base faster since they understand the framework and common idioms associated with it.

Where I work, we just had a bunch of new hires and they're being productive within the first couple weeks because they know React, and our app uses React Native.

React-knowledgeable devs are in high demand right now, which drives smart devs to learn it and garner experience with it, which makes it more desirable to use as a tool in your stack.