I'm a counter example of your claim. Migrating away from React did made the complexity of my app a lot more manageable and unlocked new business opportunities that would have been impossible with React without following the JIRA route of making the software worse for 99% of users because 1% of those needed something. The project in question is Filestash (https://github.com/mickael-kerjean/filestash), what made me switch are those 2 reasons:

- Performance ceiling. Past the point where you have used all the react specific optimisation tricks (useMemo, etc...), React just gets in the way, once you start to optimise things to reduce the memory footprint, optimise for 60FPS, dig into heap snapshots and allocation traces, your life starts to become miserable where you need a complete understanding of not only your app but also the inner working of React, and the intersection of both React with your app. At that point, you either accept the ceiling or rewrite everything to vanilla JS and have complete control over every piece of the code you are shipping to the client

- Extensibility. I am now shipping plugins which patch frontend on the fly without any build step. In practice, after a plugin author packaged their plugin (as a zip file containing a manifest), the patches are applied in real time by the server without a prior frontend build system (open up the demo instance with the network tab open to see this working from: https://demo.filestash.app/). This powers themes with icons swaps, new behaviors (e.g. a "recall" button for files in Glacier), and other things plugin authors come up with that that makes the app far more customizable and opened for new niches without falling onto the JIRA trap