Sure, if a "tech company" can only make money by selling in-house developed technology, and not by packaging in-house developed technology into other products,

Sure, if a "tech company" can only make money by selling in-house developed technology, and not by packaging in-house developed technology into other products, then I concede the point. There are fairly few "tech companies" by that definition. I still think your rephrasing of the characterization is somewhat unfair to Google. They created their main business by developing the technology to enable it, and they have gone way beyond "some contributions" to software and systems technology in support of it.