I like this definition, but I think it breaks down even if you're not trying to be clever. AWS is a tech company. Amazon is not a tech company, it's a retail store. But AWS isn't actually an independent company, it's just a division of Amazon. So we've got a retail store hiding a massive tech company because the retail store is even more massive.

I think this is less a flaw of the definition and more a sign that Amazon should be broken apart and AWS spun off as an independent company.