You can run it, though, which is the point. It doesn't require a supercomputer or mainframe. It can be cloned with a combo of dynamic LISP (flexibility/safety) and static LISP (low-level/performance) where latter might use Rust-style safety as in Carp. You can still isolate drivers and/or app domains in various ways for reliability as in JX OS. Necessary components are there for modern, fast, desktop, LISP machine with its old benefits.
People just use monoliths in C instead & call it good design/architecture despite limitations. Saying "it's good enough for my needs" is reasonable justification for inferior technology. Just not good to pretend it's something it isn't. When you don't pretend, you get amazing things like the BeOS or QNX desktop demos that did what UNIX/Linux desktop users might have thought impossible at the time. Since UNIX/Linux were "better." ;)
People just use monoliths in C instead & call it good design/architecture despite limitations. Saying "it's good enough for my needs" is reasonable justification for inferior technology. Just not good to pretend it's something it isn't. When you don't pretend, you get amazing things like the BeOS or QNX desktop demos that did what UNIX/Linux desktop users might have thought impossible at the time. Since UNIX/Linux were "better." ;)