I would say most criminals laugh at the criminal system as far as shoplifting. I bluntly say that as a person who's been in that area, and not just in criminal law but my parents had a retail store for 40 years. Criminals laugh at the justice system. I'm going to say that they're taking it much more seriously now.
In relation to private security firms, I think civil liability, just like evolution eliminates the stupid, is going to eliminate the stupid people who don't do proper training. It's going to eliminate those companies that don't train their employees properly. Sooner or later they won't be able to get insurance, and sooner or later will not be able to have a security firm. Bluntly, lawyers like you and me are the people who take them to court and sue them for whatever they're worth, and we get insurance payouts. As a result, insurance companies won't cover them any more.
I think yes, it will take some case law. It will take some time, but sooner or later those companies will have to train them properly. I learned that when I was doing litigation in relation to a bar that I sued. I could not believe how much training their employees went through.