Here is an idea that I think would be a self-correcting process for the various budget Chinese dealers...
Open a small local retail area in their warehouse staffed by the same people who currently handle the rest of the business. Carry a small quantity of the most popular items and let local people (customers) try out the merchandise in the showroom before purchasing.
This would eliminate the "bad" products where they are all bad (DD free light for example) because it would be embarrassing. Someone would ask to look at that light, put in a battery and turn it on, and it would fry! If this kept happening the dealers would weed out their own bad products.
For products where not every one is bad but where many are the same thing would happen. The dealer would be quicker to drop inferior manufacturers rather than just write it off as a cost of doing business as is (apparently) currently the case.
Most of these companies don't have any face-to-face contact with real customers or with their own merchandise really. Opening a showroom would correct that problem.