I am on AP1/MCU1 and outside the echo-chamber on this forum that are part of your crusade, people I actually know (not through a forum) in the same boat as myself, who purchased around the same time as me (2016) agree that v9 is an improvement on v8. ~110k miles in ~3 years, you'd think I have encountered ALL those issues and joined the hate club right along with you. But alas, I like v9 and I look forward to getting v10, even though I will not benefit from AP updates or sentry updates or game updates or whatever else my MCU will not support. I want to see what improvements I get on an "old" Tesla. When we get our next X, I will enjoy comparing my "legacy" X to the new X and seeing how far the company has come along.
You enjoy the crusade... I wish you the same success you've achieved so far in it.