I don't get it either. Nothing in history has come close to the current web platform. There has never been a language/runtime/framework/system where you could have this much flexibility, that "installs" in literally seconds (from a cold cache, never having been there in the first place), and works on every platform under the sun (not just linux/windows, but mac, android, ios, windows phone, ubuntu phone, my TV, my car!).
I see people in this thread talking about how it takes them 10X longer to develop for the web than it did for a desktop system, and i'm just sitting here confused as for me it was the exact opposite. I remember having to setup a development environment to get a java swing application ready to start working on. I remember the goddamn readme I needed to write to ensure that the next developer working on my GTK+ project had the right environment, the right libraries, the right platform, and the right compiler. I remember having to find some bullshit bindings to a C library for my python project that really half-assed the implementation, but it's all I had because that C library is the "defacto standard" for what it does, so I need to just deal with it.
For me the web has been such a breath of fresh air. A package system that works so effortlessly that I don't need to spend an hour deciding if that package is worth the pain of setting up another virtualenv, I don't need to worry that this library only supports Java 6 while this other one only supports java 7 and I can't have both (even though I only need the Java 7 one on this project). I don't need to worry that the next version of Windows will break GTK and my project won't support that platform and there is nothing I can do about it.
I run `npm install`, and in a few minutes, every developer with node.js installed can compile, run, modify, and deploy my code. And when deployed, every person with a browser on the planet can run it in seconds. It's amazing.