multi-memory

Interesting! https://github.com/WebAssembly/multi-memory/blob/main/propos... The scaling point is what I was thinking of. "As long as Wasm memories are limited to 32 bit address space, there is no way to scale out of 4 GB memory efficiently. Multiple memories at least provide an efficient workaround until 64 bit memories become available (which may still take a while)." So pretty similar to launching several processes on 32 bit NT or Linux, each having their own memory space.

Wasm64 will soon be everywhere if you want more than 4GB of address space. No, I was saying you could simulate larger heaps by selectively paging data memory in and out, you would still need a way to represent your max heap size. Wasm also supports multimemories, https://github.com/WebAssembly/multi-memory