If you really read what I wrote above - there is no "monolith" (and yes, Google is everyone's favorite Boogeyman). AdTech is a primordial pool all kinds of actors, each of which has found a profitable niche to "add value" (or to bullshit partners about "adding value").
I spoke of the network in specific. Whether we're discussing one firm dumping industrial quantities of sewage into the internet, or 10,000 tiny ones, doesn't really change at all that there's industrial quantities of sewage.
I'm critically uninterested in the fictions of the business idiot class. I'm sure for many purposes it's important for all the papers to have the proper LLC's on them. For the purpose of burning it to the ground though, it's not overly important.