I can't remember where I heard this or who said it, but I do like it and use it as my own definition.
A tech company is a company whose product is "easily" scalable with a few taps of the keyboard and clicks of the mouse. A game development company is a tech company. Selling one, two or a few thousand units is not that big of a deal. Now, we can argue that scalability in terms of cloud services is an issue. Think Steam for video games. But generally, there's little difference "work" wise between selling 10 copies and 10,000.
A not tech company that uses a lot of technology, but again, is not a tech firm, let's say Haas. They build high-end CNC machines. Manufacturing one or two machines is not negligible. Well, kind of. Compared to them. They build like a few hundred a month. But lets say they want to build a few thousand. That's a big deal. That's more manpower. More equipment. More materials. More warehouse space. More planning. More everything.
But Autodesk selling Fusion 360 (modeling program for CNC milling) is a tech company. Because it's generally meaningless if they have 1,000 licenses a month or 100,000 licenses a month. Production wise. All the upfront work was done for the product and now it's a matter of people giving up their credit card numbers.