I see you've been busy! Of course the Shaders... That's of course what I use. But they are nothing but a language to write in so it may run on a GPU. Shaders are also one of the 2 only ways to run compiled code on the client. V8 (Chrome's JavaScript engine) also does compilation to native machine code, but it needs to inject a lot of checking code to make sure everything is okay. This is due to the flexibility of JavaScript: Any variable can have any type of contents.
Note that OpenGL is owned by Khronos Group and isn't open source. It actually isn't source. It's an API, a set of rules of how to use a GPU, really. The implementation is where the source is at, and it's created mostly by 3D Card manufacturers, and for linux it's indeed open source. WebGL is just a shim that the browser puts between JavaScript and OpenGL so that JS can use OpenGL. This is again not open source, but just an API. Actually, none of the things you mentioned are open source. They are standards. Contracts of how to use components.
The language you use to write software in, whether C++, Ruby, PHP, JavaScript, GLSL (Shaders!), Pascal, etc, is mostly irrelevant. The thing is, you can write most anything in most any language. Of course, some languages run slower than others because of what system they run on (CPU vs GPU) or how many run-time checks they perform (JS, PHP) or whether it's compiled to machine code (C++, GLSL, Pascal, some JS) or not (PHP, some JS). So certain things care not possible to make in certain languages due to space-time constraints. (No room in memory for all the data you need, or the processing takes too long to be viable).
Open source has however enabled rapid development through re-use of components. But rapid development is nothing new. Libraries for all sorts of tasks have been around for decades.
Web 3.0 doesn't exist. Nobody knows what it means. Web 2.0 is vaguely defined at best and indicates something like the use of scripting and ajax-like interaction in the browser, enabling things like gmail. Web 3.0 is something people want to push saying we're making progress of some kind. But no one can agree on what Web 3.0 is, so it's really nothing.
Graphics 2.0 is an even vaguer concept than Web 3.0 and I can't figure out what it would mean.
As a last note on this I want to say that because it doesn't matter what language you use (to some extent, of course, if your stuff doesn't need too much memory or processing power), good software is not based on a clever use of libraries or platforms. It instead solves a problem at the conceptual level. The idea is what matters, not what language it is written on or what platform it runs on. As a matter of fact, many languages and platforms should provide the same solution with a way to exist in the real world.
The software I'm working on for instance has gone through 3 iterations with more or less the same engine/idea.
First I developed a CPU-only compiled app. I then decided to make the display faster by using the GPU, so OpenGL came into play. That worked very well and after seeing some of the Chrome WebGL examples, I realized I could run it straight into the browser. Nonetheless, none of these technologies has shaped or defined the engine itself. The engine is the secret sauce that provides 99% of the value of my sep system. The easy web access is a small bonus. But note that it doesn't matter how easy the access or use of something is, if it doesn't do well what it needs to do well then its value becomes negligible.
And vice versa, slapping a bunch of buzzwords onto a poorly working system and bolting on "the web" or "technologies" isn't going to improve the value.
So, I think the future of color separations isn't Web 2.0 or 3.0 or OpenGL, WebGL, JS, HTML5, etc, etc... , it's simply easier shirt printing and better looking shirts.
Ideas can never be super-rapidly developed. They are almost accidents. Ideas happen and cannot be forced into being. Ideas create solutions. Development only creates implementations of these solutions. The inventor is to the factory as the idea is to the development.