The modern serverless paradigm is a way to give these more traditional computing runtimes/languages a lot of the features of Erlang/OTP.

The downside to having all of these things in services on the network and outside of the runtime is latency. Imagine a runtime where everything is a message, everything goes into inboxes/queues but passing many of those messages is zero-copy, doesn't hit a network interface, and going from the calling code to the called code isn't even a OS level context switch -- so the message is written to and read from a core/thread's local cache lines.