Negative that is a common mistake made by many new ebayers. Just because its a popular item doesnt mean you will make profit on it.
Most high demand items have many sellers oversaturating ebay with the same product bringing the selling prices down below wholesale value. This basically cuts the small timer out of the equasion because they cannot buy enough bulk to get a price worth profiting on.
You want to find low demand products that are hard to find on ebay. There are always buyers looking for such items. And generally this will allow you to sell the item sometimes above retail.
Its tough finding a nich product. But many do all the time. Others just follow the flow and buy into closeouts and bulk liquidations to make thier profits.