To people like the grandparent, that is the only thing that matters at all. It's not a technical problem they have but an emotional one. They do not want the code they write to be a second class citizen to the code someone else writes, and they will absolutely be ecstatic to see us throw away the last 15 years of progress and start from stratch in order to alleviate that problem they have.
Maybe Mozilla should try writing their entire browser (VM included) in JavaScript/asm.js and let us know how that goes.
The use of XUL and the resulting UI clunkiness (speed, responsiveness, nativeness) are pretty well known.
A world in which only the vendor gets to write low-level code sounds is a terrible division of labor.
What you describe as bleak is a much better future than what we have now. At least with Mozilla's proposal we will have a well defined low-level optimizable javascript "assembly", whereas now we just have Javascript itself.
We never had access to the use of SIMD intrinsics in browsers in the first place, anyway.
For that, use native.
Yes, exactly. I want it all: native performance, security, open platform.
Google is making attempts to tackle this, Mozilla keeps trying to shove app authors back into the JavaScript box.
The problem is by trying to have "all" we might get less than what we have now.
NaCL for example is a horrible "standard", as far as specifications.
And if companies are allowed to build whole native closed source castles in the web browser, we might return to the era of Active X and Flash. Maybe not in the sense of less security (a common Active X issue), but surely in the sense of less interoperability, transparency and end user control.
You would basically just be running native apps in the browser. Why not do it in the desktop or mobile and let the internet be the open, not opaque, platform that it mostly is?
Web apps are not documents.