JVM, Python and WASM are more like the SECD [0], not a plain stack machine, by use of a local environment. BEAM (for Erlang) is a register machine. And the JVM and WASM get compiled to code for register machines, with the VM stack not present (in a concrete form) at runtime.

> a stack-based VM is relatively easy to optimise for a register CPU.

You get SSA for almost free (just phi the stacks at control joins), but after making SSA everything is the same regardless of stack- or register- VM.

[0] https://academic.oup.com/comjnl/article/6/4/308/375725?login...