I'd like to share an example. (hopefully this will translate).  Years ago, my business model included installing DirecTV.  We installed alot of them.  We weren't a dealer, just a contractor.  But the money was very good. $150 for an 18" dish and 1 receiver, $50 for each additional receiver. 

As time went on, the contractors started to cut each others throat. I can picture them saying, "I'll do it for $10 cheaper" then the next guy cuts his throat and so on down the line.  Meanwhile, DirecTV was still paying the same.  

Fast forward 15 yrs.  the average pay in Michigan for a DirecTV contractor is $70. for the dish and 1 receiver, and $20 for each additional receiver.    

Moral of the story, if you are willing to work for customers who purchase on Ebay, Amazon, etc.  YOU WILL work for those customers, because you are effectively killing the industry.  

At some point, you have to look at the big picture.  You might get paid today for working for Ebay customers, but you'll starve to death tomorrow.  

The thing that they don't get when they purchase from Ebay is YOU.  I don't know how long you've been in business, but I guarantee that you've never had a customer say to you (when bidding against another company)...I'm going to go with the XYZ system.  They ALWAYS say, "we're going to go with YOU."  that's what you're selling, not the product, you're selling your service.

I'm not directing this toward any individual.  This is just a blanket statement.