@uzairali, your observed difference between old models on CGT and TS, might be because the two marketplaces have different alghorithms of search result sorting. I think TS prioritizes model's performance in terms of sales and CGT prioritizes model's age, i.e. newer models are scored higher.
Regarding 400 models, i can only second what trimitek said - there's no magic number that would let you expect stable income. There is one seller at CGT with over 100 000 models and i think he hardly sells anything. On the other hand there are few sellers with less than 100 models (some have of them have much less) and it looks that they're performing excellent. In any case, no matter how many models you have and how good they're performing at the moment, you can't reasonably expect guaranteed income for the rest of your life. This is very fast evolving business and if you look at the best models of 10 years old, they are now looking very dated and has almost no value at all. If you want to stay afloat, you must constantly add to your model's collection. Even more, you need constantly learn new things and techniques to stay actual in this business. And despite your best effort, it is possible that 10 years ahead, you won't be able to earn for living from selling models, because technology will evolve to such extent, that everyone without any special knowledge will be able to produce highest quality models almost effortlessly.
