What is happening

Did you have better sales before or did you just started uploading 3 months ago?

Well, 3D marketplace will be worse and worse to compete every year, so don't get your hopes up. ;)

If you just started uploading then just wait, it takes time.

Just keep making what you enjoy, research other top artist work and improve your models.

270 models and no single sale in 3 months? That's very strange, i said to myself, but then i went to OP's profile, picked random model, looked at how it's published and i think i know the answer - if you put zero effort in publishing your work, expect zero sales.

Lemonade is right, models are good enough, at least , so it seems, but the buyer needs to know more about the model, a single render does not give all the data needed, at least, you should do a turntable of each model, animated or not, and, overall, show your wireframes, some renders with different lighting can also help.

I had just picked some models at random and always found a single image, any buyer in the same case will dismiss the model without further questions.

Well, this is better if not perfect.
You need to sell trough the images, you actually sell trough images, so you need the better images you can.
From this viewpoint, your images are poor, not bad, lighting seems to be an issue, lack of composition is another, you can improve this don´t worry.
But these wireframes can´t sell anything, they show a lack of experience in modeling, any pro will notice it, this is, for me the main issue.

Also price is an important factor, for exemple selling this full bedroom which is really beautifull for just $ 7.5!!! can give the impression that is stollen and many potantil customers will avoid it and maybe don't even give it a look, for such price they can also wait for something like miSsed textures or bad support...

My opinion: sometimes i feel CGtrader is going 3dExport's way or just experimenting with some show/sales algorithms. I had similar situation in februar 2019, when my sales and views stopped. Needed a lot of hard (and stupid) working for resurrecting sales. And I done that. I have much better sales after it. But I feel, "februar" will come again very soon. Because during last CGT's Halloween sellout I sold NOTHING. Yes, i have way more income than year ago. But I'm looking at sales dynamics and have no optimism. And in segment of models for 3d printing is very hard to compete with big studios, armenian, russian and indian modellers selling stolen models or models that they got via "slavery". Every month I have more and more work but less and less faith in good perspectives modeling jewelry. Last year CGT don't gives or shares motivation for modelers and sellers.

可能是需求的问题吧