If resellers insist on following the crowd by trying to sell what others appear to be successfully selling they are condemning themselves to low or no profit margins.
Is it better to sell 5 items a day at a profit margin of £20 each, or to sell 20 items a day at a profit margin of £5 each? Same money a lot less work.
The way to do this is to think outside the square, and find your own niche, then buy small quantities direct from the factories, not from dropshippers and wholesalers. It can be done, and I have taught many people how to do it despite the fact that most people will tell you the factories will quote big MOQs.
Finding a niche can be achieved with a little thought. What about your hobbies and those of your friends? Or trades experience or employment experience? Just ask yourself what products do you buy for your hobby? Are they easy to find? Are they delivered promptly? Are the prices reasonable?
If you answer no to any of these. you may have found your niche. You know something about the product, so now you research it thoroughly so that you are an expert on that product. You will know what it sells for and you will work out how to sell it yourself. You will also know your cost of selling, such as eBay fees and postage etc.
This enables you to know what is the most you could pay to buy a small quantity so that you have a big profit margin.
Now you can start sourcing the product, but you must buy direct from manufacturers if you want real profits. Take great care with this because the majority of sourcing websites have large numbers of suppliers listed who claim to be manufacturers and are not.