Second-guessing the modern web
Lot of good parts
The high performance parts aren’t React. Mapbox GL, for example, is vanilla JavaScript and probably should be forever. The level of abstraction that React works on is too high, and the cost of using React - in payload, parse time, and so on - is too much for any company to include it as part of an SDK. Same with the Observable runtime, the juicy center of that product: it’s very performance-intensive and would barely benefit from a port.
The less interactive parts don’t benefit much from React. Listing pages, static pages, blogs - these things are increasingly built in React, but the benefits they accrue are extremely narrow. A lot of the optimizations we’re deploying to speed up these things, things like bundle splitting, server-side rendering, and prerendering, are triangulating what we had before the rise of React.