Great job bridging a lot of the inferential distance between most readers and SSC’s brilliant but obscure ramblings!
Closely related to many of the points you make here is a pair of essays I wrote in Ribbonfarm, if you are interested;

http://www.ribbonfarm.com/2016/06/09/goodharts-law-and-why-measurement-is-hard/

https://www.ribbonfarm.com/2016/09/29/soft-bias-of-underspecified-goals/