As to executables, I think the big issue is that people keep on packaging some variant of Node-Webkit into these sorts of programs. What we need is something like the JVM for Node-Webkit: install once, and then apps only have to ship the application code (like Java apps don't ship with a JVM most of the time).
I think Firefox and Chrome have things, but we need that be unified (and I'm not sure if they're too sandboxed for local apps)
Firefox had things (XULRunner, and later running it via Firefox via WebRT). I have no idea about Chrome.
Experience learned during the XULRunner era is that Mozilla doesn't really want to be a platform, so they don't care very much about API changes. This means that using a shared runtime means apps will randomly break as the runtime is upgraded. Alternatively, you can attempt to keep multiple versions of the runtime around (.Net-style); but since releases are every 6 weeks and downloadable applications don't tend to have that kind of release cadence, you end up with essentially one copy per app anyway.
If the platform actually acts like they want to be a platform (the way Qt does, with supported stable releases spanning years as an app gets developed), that might work?
> What we need is something like the JVM for Node-Webkit: install once, and then apps only have to ship the application code (like Java apps don't ship with a JVM most of the time).
You mean like... a browser? I mean why re-invent the wheel when it's right there. Web standards are already available or are being made to access more OS-specific stuff (like file access, desktop notifications, background processes, offline modes), etc.
I think Firefox and Chrome have things, but we need that be unified (and I'm not sure if they're too sandboxed for local apps)