A winning item is not necessarily an item that sells the most units.
Pretend you are on Reddit reading about closed ear headphones. After reading all sorts of in-fighting about quality and sound signature, you decide to purchase these headphones at the non-trivial price of $299.
Some Google searching takes you to Crutchfield, where you buy the item.
This is where Crutchfield has a job to do ... if you are in Analytics at Crutchfield, your job is to measure the subsequent value of customers who purchase this item via Google (divided by search type and/or PLA etc) vs. all other items via Google ... and how those customers generate subsequent value via Google vs. via other channels.
If an item delivers customers with high future value ... again, not the channel, but the ITEM within a channel delivers new customers with high future value, then the ITEM is a winning item.
We just define the term "winner" differently.
Make sure your Analytics Professional is performing this analysis for you ... often. The item driving a first order is setting the stage for the remainder of the customer experience.