I don't know if I'd say Lisp machines really died; like NeXT, their rival architectures+platforms of the era only outcompeted them by absorbing them and becoming them. Modern processor architectures look a lot more like that of the Lisp machine than they look like its competitors of the era.

Instruction pipelining and memory caching to allow for "cheap" dereferences; a "flat" virtual memory; loadable modules that are source on disk and get JITed into native objects when loaded into memory... these are just generic features you could expect out of most architectures+platforms today. But those were the differentiating factors for the Lisp machine.