Well, you can't have a 20-year example in React, but let's say you hire a 10-year expert. Then such an individual might balk at things like, evaluate different frameworks to rewrite our frontend instead in, write an iOS app for us in Swift, write backend endpoints, decide how to make the UI performant considering the frontend/backend/database, spin up a new small service for a one-off tool.
In some sense, it's almost an attitude thing, which also reflects in what you've chosen to do in your career. As an extreme example, I have interviewed individuals who made it clear that they were a React expert and would not be willing to work on any legacy services that used jquery, any light backend work, anything.
Wow I imagine that candidate didn't get the job... I'd appreciate him if it were a personal policy more so than showing a lack of understanding for the past.
In some sense, it's almost an attitude thing, which also reflects in what you've chosen to do in your career. As an extreme example, I have interviewed individuals who made it clear that they were a React expert and would not be willing to work on any legacy services that used jquery, any light backend work, anything.