Not sure if it's related to recent sales slow down, but if you have published new models recently, you may notice that there's something odd going on. Usually when you publish new model, it appears somewhere near the top of your own feed and then depending on how it performs, it may stay there for a while, or gradually sink towards the middle of your models pack. This behaviour has changed since couple months, now whenever you publish new model, it is placed right at the very bottom of your page and it stays there no matter what. It is also true that newly published models now attracts dramatically less views that they used few months ago, so i assume that they are also appearing at the bottom of the search results when viewed by customers. Needless to say that it's almost impossible to get any meaningful sales when your models are out of sight of potential buyers.
I've been neglecting publishing of new models for a few years, but recently decided to update my shop. I'm putting significantly more effort in producing new models, i'm making them better than i ever did, but it's very hard to keep motivated when you see how situation in cgtrader is degrading month after month.