Erlang is not just classes with a thread and a queue attached to it. Anyone can do it. It is also fault tolerance. How many of the actor libraries support creating large number of processes that have isolate heaps? How many have completely concurrent and pause-less garbage collectors?

The closer abstraction is probably OS processes + IPC. Then you get closer to the spirit of it. And Chrome browser and other software take that approach. It isolates faults. But well, you have to do a lot more work around it and those are not exactly light-weight. Erlang processes are only a few K of memory each.