And some's details were published for other people to learn from. Anyone wanting to see how they implemented it can google LISP and Scheme machines, hardware, processors, and similar search terms. I recall one implemented cons directly while hiding GC behind memory interface. The programs didn't even know there was collection and it happened in parallel with execution without stopping execution. Great stuff. Many of these give software and hardware implementation details where they could be copied in FPGA's.

Closest thing I've seen in a modern product is Azul Systems' Java processors with concurrent GC's. So, at least one company is benefiting from the old wisdom.