So if that's the line you draw, it extends further than just tech giants.
Pop sockets got in a fight recently with Amazon, because they wanted to stay FBA in order to have better control of selection and pricing, but Amazon was trying to force them into a more traditional vendor role.
And what happened with PopSockets didn't quite work that way. They were already a vendor on Amazon, and they wanted to remove themselves as a direct vendor and designate a single reseller as their "approved" FBA on Amazon.
So they wanted to change the terms of the agreement, Amazon said no, and that was that.
Batteries, clothes (lots of clothes), backpacks, these are all products that are cheap to produce and where brand loyalty plays a large role. People generally trust the name Amazon. It's not rocket science to realize people want cheap clothes and batteries.
https://www.amazon.com/b?ie=UTF8&node=17602470011
https://www.recode.net/2018/4/7/17208804/amazon-private-labe...
Though many of them choose brand that are not as obviously connected with the house. Like half the stuff at Walmart is actually a house brand.