I dont disagree.
If a person makes an informed decision that they are willing to share their personal information in exchange for a service like Google, Facebook, etc, that is fine in my books.
One point I would push back on is this, the argument that devs built the site and therefore the company deserves all revenue that comes out of the site is wrong in my books. If you and I were no on those sites, then the site is worse off, not because we are unique but because without individuals contributing to the site the site is less attractive. We are the content they are selling. Come see all your friends in one place. But if we stop using it, then Facebook would turn into MySpace. See what I mean?
You're right, we are the product they are selling and the sites do need us. As long as FB offers compelling products, people will continue to use it, even if it means giving away personal data. This has been a very successful business model that has come out on top in the free market. I don't think there is anything particularly wrong with it. To me, privacy doesn't have any tangible value and is not the same as security. For example, there is nothing private on Steemit - you can even look at how much I have in my wallet. However, Steemit is very secure and you would have to come to my house to find my private key and steal my money. Security trumps privacy, and companies like FB and Google has very strong incentives to keep things secure.