Without commenting on Haskell, et al., I think it's important to start with "good models of processes" and let these interact with the best we can do with regard to languages and hardware in the light of these good models.
I don't think the "stuckness" in languages is other than like other kinds of human "stuckness" that come from being so close that it's hard to think of any other kinds of things.
Thanks! That helps reaffirm my thinking that "good models of processes" are important, even though implementations will always have limitations. Good to know I'm not completely off base...
A good example for me has been virtual memory pattern, where from a processes point-of-view you model memory as an ideal unlimited virtual space. Then you let the kernel implementation (and hardware) deal with the practical (and difficult details). Microsoft's Orleans implementation of the actor model has a similar approach that they call "virtual actors" that is interesting as well.
My own stuckness has been an idea of implementing processes using hierarchical state machines, especially for programming systems of IoT type devices. But I haven't been able to figure out how to incorporate type check theorems into it.
I don't think the "stuckness" in languages is other than like other kinds of human "stuckness" that come from being so close that it's hard to think of any other kinds of things.