I skimmed through the blog post, and it seems to me that they are not claiming they invented something new, just that they are adding this to Swift language.
(Distributed) actor model is nothing new, but I definitely wouldn't classify it as something that's common in other languages. To my knowledge Erlang/OTP is the only mainstream language where this is part of the standard library.
There are implementations for other languages, such as Akka for Java/Scala and Orleans for dotnet, but most languages (sadly) don't have a battle-tested implementation of this.
(Distributed) actor model is nothing new, but I definitely wouldn't classify it as something that's common in other languages. To my knowledge Erlang/OTP is the only mainstream language where this is part of the standard library.
There are implementations for other languages, such as Akka for Java/Scala and Orleans for dotnet, but most languages (sadly) don't have a battle-tested implementation of this.