Well, your first point is again "let's not use assembly language, it lacks a standard library". Yes, the remark is true, but this just means that we lack higher

Well, your first point is again "let's not use assembly language, it lacks a standard library". Yes, the remark is true, but this just means that we lack higher-level tools above DOM/CSS/JS. For your second point, I somewhat disagree. JS is now quite efficient. Not CUDA fast yet, sure, but much faster than, say, Python, VB, and often much more memory-efficient than Java. To the point that some video games have been automatically recompiled from C/C++ to JavaScript (through Emscripten) and work quite nicely. Similarly, DOM/CSS are inefficient for really low-level stuff, but suddenly become pretty efficient for animations, for instance. And, really, the biggest argument for keeping the DOM is not technology, but community: many people know how to use it to do cool stuff. But yes, canvas + JS or WebGL + JS are also available, for applications that require them.