And then we'd have had people writing applications that Lisp isn't suited for complaining at what could have been if only we'd gone with a simple register architecture. Don't get me wrong - I believe in owning the whole stack, and I'd love to see some Lisp machines. I fully believe that something like this may reappear in the future. But let's not kid ourselves: none of these singular visions of simplicity is going to be good enough for everything.