It really isn't, as OOP languages don't traditionally provide robust mechanisms around immutability. And why would they? The core design of OOP is to wrap mut

It really isn't, as OOP languages don't traditionally provide robust mechanisms around immutability. And why would they? The core design of OOP is to wrap mutable state behind methods which control that mutation. OOP was in many ways a reaction to C; shared mutable structs are harmful, so let's invent privacy. Most of the languages which are suggested to be superior alternatives to OOP in this thread have immutable data records and algebraic data types as core building blocks. These are very different than C-style structs, as they can provide stronger safety guarantees without a massive ream of boilerplate. A class or method interface promises unfortunately little around essential topics like mutability, concurrency, or termination.