In a sense that's a valid point, but what we have seems inferior in this regard. My machine is running a huge amount of individual, uncoordinated runtimes. Often there's layers and layers of uncoordinated bloat, communication overhead and everyone does his own garbage collection, scheduling format translation, gui rendering and so on. It's incredibly wasteful and the only thing that patches over it is that my computer is fast enough to handle all this crap.

/rant

I get that all of this has reasons, often historical. PC/Internet adoption just grew so fast during 80's and 90's that nobody even had the time to think it all through and design a coherent system. Even new OS's and runtimes have to carry over all this legacy stuff. I mean I get it and as a web developer I'm probably more part of the problem than the solution. But boy would computing be simpler, more powerful and expressive if we could just start over and lean on the ideas of (mostly) early, holistic visions and prototypes of personal computing.