Interesting idea, but I'm not sure I agree. I was doing a lot of telephony/mobile back in those early 1990s and there was a huge amount of formalism. We tried to model everything as FSM that transitioned states based on received messages. We even used code generators to generate code directly from diagrams. I believe Erlang grew out of that same approach. And initially, systems that failed would simply restart by default.

Then the idea of adding a supervising and observability was a natural addition to these systems.

That said, I think OTP is a great tool for modeling failure domains and I think it does a great job.