> Dozens of what? Browser plugins? I don't have to imagine, that's the world we live in.
That's quite a stretch. There are two browser plugins that are in broad use on the web: Flash, for fallback audio/video support and some casual games, and Silverlight, for Netflix. Both are dead technologies when you consider mobile web; even if you're only thinking about laptops/desktops, both Silverlight and Flash have essentially been abandoned by their creators, and the web platform has almost entirely subsumed their original purpose for existing, currently with the exception of DRM.
Personally, what I'm hoping happens is that we get one, single better compile target, and languages can just target that — giving the web a broader selection of languages without the fragmented nightmare (and security nightmare) of introducing dozens of new plugins. This is something that browser vendors are currently working on: Google with PNACL, and Mozilla (and, to some extent, Google as well) with asm.js. I hope we end up with PNACL, but a sufficiently optimized asm.js would serve the same purpose, albeit with a more difficult debugging / performance optimization story.