Hi, I attempted to address your argument in the section roughly titled "Node.js has super concurrency!". You may have to scroll down "below the fold", so to speak.

I presented two different ways of writing a single-threaded, event-based function that can handle "an awful lot of concurrency without ever thinking about threading issues or managing thread pool size to balance memory and concurrency". Essentially, it is possible to get good concurrency in a single thread without the use of many nested callbacks or abandoning the language's natural control flow primitives. It's not necessarily the case that you can't have both event-based concurrency and sane code.