>> the mechanisms are totally separated from the physical reality.
> There were honest to god LISP machines
As LISP-flavored stack machines, yes [0]. Alas that Linear Lisp [1] never received a hardware implementation [2].
To those exploring high level language architectures, forget not also the noble SCHEME-79 chip [3]: a Von Neumannian register machine, but one which executes a SCHEME interpreter microcoded in LISP.