There is already a strong effort in Ruby land - check out http://artoo.io/. Artoo was developed with robotics in mind but it is not limited to that domain.
You could - but V8 is actually much faster than Ruby or Python, and JS syntax is quite good for I/O. Better than that, a ton of people know JS and the more developers find this accessible, the better.
> V8 is actually much faster than Ruby or Python
Actually, they are compiling to Lua bytecode in this case.
> JS syntax is quite good for I/O
And you can pass around blocks in Ruby.
And you can't in Javascript? Sure, the syntax is a little clunky, but the semantics are precisely the same.