Drag and drop/scroll should work on the real DOM not the virtual DOM, no? I use Drag and Drop in a web app (using Om, which is a clojurescript library built on top of React) and it works just fine across all platforms.
The DOM is not a view. In fact it stands for Document Object Model :P I know it's confusing since it's where you create the view for your app, but the DOM is actually a model of your view (i.e. the V on your app's MVC is built manipulating the M on the browser's MVC).
Why can't the web draw at 100 FPS from immutable data? Because the web renders through constraints based on the DOM, and constraints cascade, which is a problem more akin to physics in games (which are mutable for a reason) than their graphics. The bottleneck is updating such model.
Also, game physics constraints are usually faster to calculate because action at a distance is unusual and there are optimizations like quad-trees. In web pages, inserting a single DOM node can trigger a huge change, making it more like simulating hydrodynamics that the common solids found in videogames.
You bring up some interesting points. I guess you could compare the DOM to the OpenGL/DirectX scene, with some differences. I'm not entirely convinced that the graphics rendering is less complex though, considering occlusion lightning etc. My main point was really yhat re-building the entire scene is entirely possible and a lot easier to code than manipulating a stateful scene.
I guess physics is stateful since the programmer only sets initial conditions and the engine moves it forward, so the final state is unknown to the programmer.
Dom is a fine tool but I would like a better separation between the model and the view, which re-rendering gives you in a straightforward way. The other way is data binding, but it's considerably more involved and probably not worth it for 99% of the cases IMO.
