I think it isn't explored enough why Lisp, as such, (not to be straw-manned into the many brilliant and pioneering ideas that originated from it), has just not caught on very much. E.g. why does Google, with an army of PhDs, very consciously not let their top engineers use Lisps?
I postulate that, like Tim Sweeney's quote implies, that there really is a great cost (in terms of the problems that industrial programmers face) to the sort of extreme dynamicism that Lisps offer. Now some of the largest of those problems include what a company should do when their lead engineer quits in the middle of a project, managing extreme changing requirements, managing staff writing automated testing and creating documentation, and other things that may not be considered in pure academic study but where language choices and methodologies may make a large difference.
This has been the #1 troll on any lisp forum for 30 years. It has been explored ad nauseum. If you're being sincere (which I doubt) read Richard Gabriel