Comment by theturtletalks

You're right, but sellers are realizing that they are helping Amazon, eBay, etc. more than those platforms are helping them. For example, if you use FBA to fulfill outside orders, Amazon charges a higher rate. You're locked into their pricing and their marketplace.

I would say 85% of sellers on eBay and Amazon have their own storefront now to be in more control. They also funnel these orders into an OMS.