"My (and your) 10k, 100k, 200k line C# applications are not writable in JS."
I don't know that this will be true for very much longer, if it's not already been disproven. Javascript isn't the greatest language out there but it's gain functionality that is removing the limitations that uses to plague it compared to other languages. Slow VM is not longer true, no multithreading is not longer true. Webworkes are a little odd for sure, but they still make it possible to build multithreaded applications. WebGL/Canvas allow for some very advanced graphical applications. You can now access local storage, a database (and in node, other databases), new ArrayBuffers and such. It's a different environment now.
I can't point to any (GMail client side code must be pretty big), but I do have a 5K one that I work on daily and it's not a mess. This project is still very much in development and will grow with time.
It's not 50k and it's for sure not a project with 20 devs but even this size was unthinkable earlier.
I'm working on a backend in node to take advantage of Websockets.
I can't show you one either. But I can tell you that JavaScript, done right (which is a big caveat), is a great language. People think it's a toy because of its history (and a good number of embarrassing mistakes in its design), but it's very expressive. It has borrowed many of its core concepts from Scheme.
I think he's talking about the maintainability of such an app in the hands of your average joe programmer, not the sophistication of the language. Also, static typing does have it's advantages, particularly in that it's easier to write tools for developing and debugging those languages.
I don't know that this will be true for very much longer, if it's not already been disproven. Javascript isn't the greatest language out there but it's gain functionality that is removing the limitations that uses to plague it compared to other languages. Slow VM is not longer true, no multithreading is not longer true. Webworkes are a little odd for sure, but they still make it possible to build multithreaded applications. WebGL/Canvas allow for some very advanced graphical applications. You can now access local storage, a database (and in node, other databases), new ArrayBuffers and such. It's a different environment now.