All good things... as the saying goes. You've done good over the years; the fact that you kept plugging away at it is far better than I've been doing (because life, that's why.)

The following is not a judgement, but I want to answer your implied questions in a way...

- The figure promotion issue has been a chicken-and-egg problem ever since people stopped using Posette as their primary figure, and first became apparent when statistically nobody - freebie maker or vendor - really bothered with Judy (anyone else remember that figure? It was the default Poser 5 female figurine.) It's been a thing ever since.

- The CG hobbyist market has been shrinking for awhile - AI is only accelerating this as it moves from the 'slop' phase into something that's actually useful.** 

- The pr0n art (read: mostly hentai IMO) sector has definitely moved to AI, as expected; the impatient 'art' crowd there is only looking for spank-bank material - they see AI as a faster route to getting those dopamine hits they crave - after all, can't be wasting time actually setting poses and waiting for renders to finish.

- Poser's up-front costs make it less appealing in the face of Blender (free), DS (free), TiXL* (free), Unity (free for individual use), VRoid (free)... and more popping up almost monthly. Art has never been easier to make, and that's not even counting the rapidly expanding AI (non-porn) art universe.... and most of those tools are free as well. Who wants to pay $$$ up front when you don't have to? 

- Rendo buying Poser was a noble last effort, but sadly, unless something major and disruptive happens, I suspect Poser will continue fading away. 

Maybe someday in the future, someone trolling archive-dot-org for research material will stumble across this little genre, and marvel that people willingly put themselves through so much just to make pretty pictures.

** I will say though there's a few new AI-centric plugins and CG helper apps out there that really rock - like the LaurenDev DAZ Pose Generator.
*** TiXL: https://github.com/tixl3d/tixl