Earlier quoted context omitted.
If you want a message queue bounded to length N, then make the messaging protocol such that the sending process sends up to N messages without an ack.
The point I am trying to make is that this fundamental feature of message queues (limit their length to prevent the memory exploding) should be provided by Erlang and not reimplemented over and over again by developers.This is really a basic feature in any message queue
What happens if the message you can't add is a specific system message that allows the suspension of OTP processes for a code upgrade? Do you end up livelocked? How do you propagate back that you couldn't insert your element in the queue? Do you make message passing an operation that can fail? How would that work over the network when the message telling you something failed is lost over a netsplit? Is it a different kind of failure?
This has very deep design repercussions on the language. It's not impossible, but it wouldn't let Erlang be the same.