[zakki]

For the impact someone should compare before and after activation lock is launched.

[nneonneo]

Yes, many studies were already done on this topic. For example, in the six months after Activation Lock was introduced on iPhones, thefts in San Francisco dropped 38%, compared to the 6 months prior. https://archive.nytimes.com/bits.blogs.nytimes.com/2014/06/1...

[nicolas_17]

Activation Lock was launched in 2014 with iOS 7. It did reduce theft.