GP seems to be implying hot swapping, not Erlang, is unreliable. To which, from my experience using it in Erlang, I heartily agree is fraught. Inconsistent state across nodes is much harder to reason about. When you _must_ ensure consistency, hot swapping is reckless, especially as org size and product complexity increases.

Leave hot loading to local/development environments, not production deploys.

Loading configs on the fly can also have some of this risk, but it is much easier to reason about typically.

I heard the quote that some 50% of the mobile traffic is handled by erlang. Somehow the other 50% seems to be doing just fine (except the usual shitshow on the inside that sofware is everywhere all the time).

I agree. I don't know much about Erlang but what I've heard seems to indicate it's used for high-uptime systems that handle errors well.

As someone who is now in the rust world and very very sympathetic to the Erlang world... you both probably mean completely different things when you say "reliable". The contexts are just world apart.