Frequently the software running inside WASM sandboxes has its own garbage collector anyway, and it's not going to perform as well as a native host collector in

Frequently the software running inside WASM sandboxes has its own garbage collector anyway, and it's not going to perform as well as a native host collector in some cases. Especially if you start doing cross-language GC in order to talk to the host (web browser) and manipulate its objects. Of course, exposing a WASM GC API that can actually meet the needs of real software is tough, which is why it didn't happen... If you think WASM software is going to be efficient with its memory usage, you should look closer at the memory model and take note of details like 'you can't ever shrink the heap' and 'you can't do read-only shareable mappings'