Here is from another thread. There’s a chart somewhere around here that shows labeled vs actual from lab testing, but I can’t seem to find it.
I’ve discussed point-blank with producers and ABV and it essentially came down to two things: virtue signaling for their perceived style, and having printed labels a few vintages in advance to save costs. One winery actually had a lower ABV than labeled because the vintage was cool and labels were printed ahead of time, whereas every single other year was above the labeled.
Tons of people talk about scaling back their wines, which is probably true, but expecting the label to tell the story is unreliable at best.