Why do OS not support erlang's lightweight process?

[Jay Nelson]

The strength of erlang is not just that you can make lots of little 
processes.  It is the combination of this with the following things:

1) Fully isolated processes which are linked and signal failure
2) Failure is a fundamental assumption at all times
3) A simplified message passing scheme
4) Non-mutable "variables"
5) Pattern-based functions (makes messaging much clearer and easier)
6) Hot code loading as a fundamental function of the language

Of course, all of the above work both on the same local CPU or on remote 
processors.

If you add processes to the OS without the means to code and manage 
processes clearly, you will make a bigger mess out of the existing 
programs because the languages are not inherently defined to support 
many processes.

If you add 1-6 and remote processes, you are back to erlang, so why bother?

It is difficult to extract the essence of one substance and inject it in 
another substance with the goal of improving the deficient substance.  
You end up with an incomplete artificial substitute.

jay