> [...] a growing number of companies have diminished the concept of opt-in by choice, it is now being turned into opt-in by default.
The term for "opt-in by default" is "opt-out".
The term for "opt-in by default" is "opt-out".
By saying "opt-in by default," author is making the subtle point that positive, affirmative consent is assumed - not just that the features are literally on by default.