"[...] with strong guarantees that the data of end user who has opted for paid service is kept private and not monetized anyhow."
As an "actual programmer" myself, I don't see how that would be so burdensome to implement. The data is somehow segregated so that it's excluded from being sold to advertisers in any form. The user can have their data deleted permanently at any time.
It obviously wouldn't prevent someone from authorizing a 3rd party app to all of my Facebook data, but that is more about Facebook educating people about what they're consenting to rather than a philosophical debate about ownership of data.