I mean to replace the ones that we use today. Not the ones we used 30 years ago. General purpose operating systems. Perhaps with a distribution we can download for free and install on commodity computing hardware, and actually use today for our primary areas of work/interest.

Note the section 1.7 in your own link ("End of the Lisp machines"). The Lisp software ecosystem was never as rich, broad and varied as the C/C++ software ecosystem is today, before it died.

BTW, I only stumbled across your comment by accident, since you replied to the parent poster instead of me. Parenthesis mismatch?