The value of what they provide isn't necessarily it's cost.
That's the whole reason we trade. The value of a good is different to different people. If a book is worth £5 to me, and £1 to you, then if I give you £2.50 for the book we've both gained more than we've lost.
No the value is decided at the moment of transaction, so that's how companies can accumulate value over transactions that are deemed "fair" by both parties. You can decide go give someone $10 for bunch of apple, and the seller can accumulate value from this.
The problem here is that one side of the trade does not fully know the value they provide. When you give $10 for an apple, you know exactly what you give and what you get. When you give $0+"your data"+"your ad view/clicks" for "free Facebook service" it's really really unclear what it is you're giving to Facebook and what it is Facebook is giving you.
Maybe the world is starting to believe that "it was profitable" is not always a defensible position? Perhaps an age of consumption is passing towards an age of ethics. Time will show.