I work on a large code base that was built in .NET 4 with a lot of jQuery for the front end. We're modernizing it, but it's very slow work. A significant part of the work is improving the organization of scripts, of which there are thousands. We're not even prioritizing getting rid of jQuery, because it works. To rewrite all the stuff that works, instead of focusing on structural matters, dependency management, maintainability and security, would be insane. (And that's just the JS bits, on top of which there's all the legacy .NET stuff to do.) We aim to get it into a state that will leave it working and maintainable in future without excessive effort.

Sometimes I wonder who these people are who always promote this year's library or framework, then next year promote something newer. Do they work in real companies with real applications under heavy use? Have they ever had to maintain a codebase that was written more than 6 months ago? Or do they just build proofs of concept and small apps and pontificate a lot, then move on to the next job before things get serious?