I would suggest the following:
* a car company makes cars that it sells to consumers or other businesses
* a tortilla company makes tortillas that it sells to consumers or other businesses
* a chip fabrication company makes chips that it ...
... you see where I'm going with this?
* a tech company is a company that makes technology that it sells to consumers and other businesses.
Amazon is a tech company, but only because of AWS, not the marketplace or its own retail operations.
AirBnB is not a tech company. Neither is Ebay.
Maybe we need a new term like "tech-dependent company" to describe most of what are currently termed "tech companies".