My 3d asset purchases have been on the decrease long before I started using AI. Not buying as much now that I'm retired and it's a hobby not a job. Plus the bad economy and a fixed income (disability pension) means less money for non-essentials like a thousand variations of the same string bikini for Vicky Whatever-Her-Number-Is-These-Days. My computer is fairly new but struggles with fully loaded Genesis figures if there is more than one per scene and I am doubtful of its ability to handle the next version of Studio or Poser without major upgrades. Which again I cannot afford, especially since the thing ain't broke and in need of fixing. Have not jumped on the Genesis 9 bandwagon and only toe-dipped in the 8.1 pool, still using Michael/Vicky 7 & 8 -- and yes, even 4. Since I already have tons of stuff for those figures and the supply of new products for them has mostly dried up, I'm not inclined to shop the 3D section very much. 

That said, I have found myself buying more brushes, overlays, Photoshop actions, Paintshop Pro tubes and the like. For the purpose of using them along with programs like Stable Diffusion or MidJourney to do mixed media pieces. So AI has actually increased my spending, just on 2d assets instead.