(I agree with other commenters' assessment about the importance of the authors complaints, and recommend others checkout the Go memory regions proposal.)

For those interested, here's an article where Miguel Young implements a Go arena: https://mcyoung.xyz/2025/04/21/go-arenas/. I couldn't find references to Go's own experimental arena API in this article. Which is a shame since it'd be if this knowledgeable author traded them off. IIUC, Miguels version and the Go experimental version do have some important differences even apart from the API. IIRC, the Go experimental version doesn't avoid garbage collection. It's main performance benefit is that the Go runtimes' view on allocated memory is decreased as soon as `arena.Free` is called. This delays triggering the garbage collector (meaning it will run less frequently, saving cycles).