I thought most of the shoplifting damage isn’t the teenager (or senior) pocketing a snickers bar but the roving bands of professional shoplifters. These people can be caught and deterred.
I think at some point the effort will be too costly for them and they’ll fold and it would make more sense to divert that effort into legit businesses.
Other way around. By installing the shoplifter-detecting cameras, the shopkeepers will lower their guard because they have just spent a lot of money and are happy to abdicate the surveillance responsibility to the computer.