Earlier quoted context omitted.
"Is it possible to create a truly safe language without the dizzying complexity?" Yes! The good news is, they even already exist. There's even at least two variants of them: Pure immutable values (Haskell, Erlang) and languages that aren't pure functional but involve lots of little execution units that can't send mutable references between the units (Elixir, Pony) which when used even slightly properly makes unaccoun…
Aren't Haskell and Erlang both GC? I don't think anyone is touting Rust as newly immutable. The only differentiator (to my understanding) is Rust's safety without GC .
I answered the question about safety. You can have the safety of Rust without the complexity of Rust. I never promised there are languages that will have every last attribute of Rust but be simpler, and even typing that sentence out should make it clear that that is fairly unlikely to happen. Adding a GC is one way to simplify Rust. All simplifications of Rust are going to come with side effects. The complications are there for a reason; the question is always, does the code you're writing right now require that complexity, or can you use a simpler safe solution? Usually the answer will be the latter, honestly. Only a fraction of programs require that level of control... but it's a very important fraction!
There are some immutable languages inspired by Rust that are trying to have immutability without garbage collection but they're a ways off from practicality, I think.