The falling shrinkage is a good indicator, although it’s imperfect for obvious reasons. Of course, there are anomalies like COVID, but otherwise the trend is clear. Also when some entity like supermarket chains or their advocacy groups tried to split up shrinkage by its causes in the past decades, even the shoplifting part fell. So there is no better statistics, and that tells that shoplifting is probably falling.

Of course, you cannot know, but statistics is quite clear that shoplifting decrease is way more probable than increase, and you need some other reasons to advocate for increasing shoplifting. So when somebody does that, it’s highly probable that not because shoplifting is actually increasing.