I agree that RAII does not solve everything - in particular, issues with memory fragmentation. However, I prefer the direction being taken by Rust and suggested by the top level poster: rather than having to run a separate thread which tries to infer which resources are no longer needed, with potentially large runtime costs, instead augment the language semantics with a clear ownership model, and thereby give the compiler enough information to generate code that runs in a stable, predictable memory footprint.