The key thing to always remember is the service being provided here is to save people time. I can never understand why poor models are uploaded even for a very low price. Anyone can make a low quality model & try to sell it on here, but they will then gain a reputation for low quality assets.
Also every now & then someone will ask me for help with a model they have bought. I am always happy to do this because I believe my assets are of good quality & every time I have been able to provide helpful support to customers.
I doubt I would be able to do this if I provided hundreds of models, as responding to support requests for lots of cheap models for say less than $10 would take too much of my time & potentially wasting the customers time waiting for me to respond - thus defeating the object of buying assets on here.
You can't buy a good reputation, but you can easily get a bad one for free with poor assets/support.