Increased severity of punishment has little deterrent effect, both individually and generally.

The certainty or likelihood of being caught if a far more effevtive deterrent, but require effort, focus, and resources by law enforcement.

It's a resource constraint problem and a policy choice. If "they" wanted to set the tone that this type of behavior will not be tolerated, it would require a concerted multi agency surge of investigative and prosecutorial resources. It's been done before, if there's a will there's a way.