Well those people lied to you then, or more likely there was a misunderstanding, because you can literally just look up the sites I mentioned above and see that you're entirely incorrect.

You don't need to be under NDA to see the hundreds of billions of dollars worth of custom built and self-owned data centers that the big players have.

Hell, you can literally just look at their public websites: https://www.google.com/about/datacenters/locations/

I am one of those "pay grades many layers higher", and I can personally confirm that each of the locations above is wholly owned and used by Google, and only Google, which already invalidates your claim that "you can count the wholly-owned sites on one hand". Again, this isn't secret info, so I have no issue sharing it.